Chocolate chip cookie variations can get a little fussy. This isn't a bad thing per se: baking can be a difficult thing to really nail, and consistency in your ingredients and techniques is a big deal.  But I'm happy to report that despite the rather gourmet sounding concept, this recipe is actually pretty simple.  You could jump right to the recipe card and probably make out just fine, but I will make a few notes here to help with some of the more important points.  I'm also going to use this space to talk about a few of the potential stumbling blocks that come up in cookie recipes like this one, and explore some possible variations and adaptations for those of you looking to continue the inexorable evolution of the chocolate chip cookie.

There are a number of complexities in other brown butter chocolate chip recipes that I didn't really get into much here.  I was thrilled with how my batches turned out so I didn't feel the need to mess around much, but but perhaps you'll find that you're interested exploring a few options.  A number of these points are addressed below.

Brown butter and toasted oats obviously have an impact on the flavour of the finished cookie, but they also affect how the dough comes together. I'm going to take a moment to address these two factors separately.

Brown butter (aka beurre noisette) is made by heating butter on the stovetop until the milk solids separate out from the (now liquid) milk fat and begin to toast.  Thanks to the Maillard reaction, the protein components of these toasted milk solids take on complex, nutty, caramelized flavours.  These browned milk solids can be used with, or separately from the melted clarified butter fats.  In this recipe, I brown the butter more than you might see in many recipes, and I mix the toasted solids back into the fat (see picture below for an idea).  We want to really amp up the nutty flavours, and to give the oats plenty of opportunity to brown.

The oats are also browned, this time via both caramelization of the carbohydrates and the Maillard reaction acting on proteins.  This results in even more of that nutty/toasty flavour for your cookies.  Grains benefit enormously from browning, which is why a piece of toast is very different from a piece of bread (or why the crust of a loaf of bread is very different from the interior crumb).

On their own, the toasted butter and oat components tend to lend themselves a bit more to a savoury flavour profile.  But when we add sweetness (in this case, brown sugar), they become evocative of caramel, butterscotch, toffee, and hazelnut.  These flavours and aromas can actually make brown butter cookies seem sweeter than they should given their sugar content - which is why we further balance the flavours with a bittersweet dark chocolate, rather than a milder milk chocolate.

Browning butter causes it to lose water thanks to evaporation.  This means that your butter will contribute less moisture to your cookie dough than it would in its un-browned state.  This problems is addressed by adding eggs (which also serve as a binder and a source of added fat/richness) and by using a greater proportion of brown sugar.  The oats factor into this as well.  In a standard chocolate chip cookie with oats, the dry oats absorb some of the moisture in the dough.  In this recipe however, the oats are saturated with butter fat instead, meaning that they won't sponge up any moisture when incorporated with the other ingredients.  Now, I will still say that this is a fairly solid cookie dough! If you're used to a very soft, batter-like cookie dough, you might be a bit surprised here.  Nonetheless, the cookies themselves bake up very nicely, and stay fairly soft as long as they're not over-baked.  It is possible to play around with the moisture content a little bit, but I'll address this below.

This recipe calls for a 1 hour resting time for the dough.  This is essential for letting the moisture distribute evenly and hydrate the flour.  Many cookie recipes (and indeed, some brown butter cookie recipes) call for the dough to be refrigerated for 24 hours or even longer.  This is a great step in many cookie recipes, but I don't think it's necessary here.  Resting dough that long allows some of the proteins and carbohydrates to begin breaking down.  These compounds can then brown or caramelize more easily, contributing to richer flavours.  The thing is, we've already kicked the 'browned' flavour into overdrive with the butter and the oats.  An extra 24 hours is overkill at this point.

Flour is a pretty big deal in cookies.

First and foremost, I highly recommend that you weigh your flour, and use the specific quantity called for in the recipe.  I can't stand the finicky 'spoon flour into the cup' style of measuring, and so I pretty much always scoop a cup directly out of the bin.  The thing is, this compacts the flour quite a bit, and can make my "1 cup of flour" different from the so-called standard.  On top of this, Canadian cups are generally metric (250 ml), rather than Imperial (240 ml).  Relying on volume measurements for flour can therefore lead to some pretty drastic differences.  Case in point: my "two cups" of flour (scooped from the bin with a Canadian cup) come in at 360 grams.  The "standard" weight (spooned into an Imperial cup) should be 240 grams.  That's a huge difference! I'm effectively adding an entire extra "standard" cup of flour!  If you're only able to use volumetric measurements, you should still be able to make great cookies - after all, it's a recipe, not rocket surgery.  But it is worth noting that you might find that you need to play with the recipe a little bit more to get the desired structure out of your cookies.

A number of high-profile chocolate chip cookie recipes call for higher-protein bread flour, rather than all-purpose.  I'm not going to get into that debate in much detail because honestly it'd make for a whole other article, but the protein content of your flour definitely matters.  The thing is, it's very difficult to generalize about protein content to an international audience.  As I mentioned in an in-depth look at making pandesal, Canadian all-purpose flour actually tends to be pretty high in protein content already.  For us Canucks, the switch to bread flour is largely superfluous in a recipe like this.  But depending on where you are in the world, it may or may not make a difference.

I recommend using standard all-purpose flour the first time you make these cookies, as a) you're like to have it on hand, and b) it very well may yield the exact results you're looking for any way. If you feel that the cookies need a bit of adjusting, there are multiple factors to consider (see below).  This means that it can be difficult to determine exactly what impact the flour itself is having.  As a general rule, the higher the protein content, the chewier the cookie will be.  If you find your cookies are too soft (not necessarily 'gooey' soft - more like crumbly and 'weak') you might need more protein in your flour.  If they're too chewy and dense, you might need less.

The oats are, thankfully, less complicated than the flour. Any basic quick/rolled oats will work nicely here. I only bring them up here in the recipe notes because the recipe calls for the oats to be broken into pieces using a spice grinder (or blender, food processor, or similar). The idea here is to produce lots of small pieces of oats, but not to pulverize the oats into flour. The image below should give you an idea of what I mean. You'll most likely end up with a few large oat pieces too, which is fine.

If you don't have a spice grinder (etc.) to break down the oats, you can try using them as-is, though please note that I haven't tried this myself.  The large oat flakes will contribute a different texture to the cookies, but I suspect that they will more-or-less bake up the same way.  If you give it a shot, I'd love to hear from you in the comments below.

On the one hand, you should probably make this recipe as-is first before messing around.  That way you can address exactly what you do or do not like about the recipe and tweak the relevant aspects to get closer to your dream cookie.  On the other hand, I'm being a little hypocritical, as I constantly mess with recipes before trying them.  If you're a confident baker and kitchen experimenter, you might be comfortable jumping right into some of these variations and tweaks.  Just don't leave me a nasty comment about how bad the cookies were after you changed twelve things, ok?

If you're interested in looking deeper into the different properties of the various ingredients in this recipe, I recommend reading this fantastic overview from Serious Eats. FYI, many of adjustments and variations can be to tweak a variety of cookie recipes!

I like to make these cookies pretty big.  I get 24 cookies out of one batch by using a small-ish (Ikea) ice-cream scoop to portion out dough.  Note that this is a flat (i.e. not mounded) scoop - any bigger and you're getting into mega-cookie territory.  You could easily go smaller however!  That being said, you're going to want to pay very close attention to your bake time, as it will decrease sharply as the cookies get smaller.  I will also note that these cookies don't spread all that much on a baking pan, so you might want to flatten out smaller cookies even more than you would the larger ones.

Do you like a cookie with a little more snap? No problem! Unlike many chocolate chip recipes, this one uses only brown sugar.  I did this in order to further amp up the caramelized notes of the cookie, and because of the added softness and moisture that comes from using brown sugar.  If you want a cookie on the crisper side, replace up to half of the brown sugar with white granulated sugar.  If you find that your dough is a little bit too floury after this change, you may want to add 1-2 teaspoons of water.

Soft chocolate chip cookies are one of those things that people write about a lot, precisely because it's a bit of a tricky subject.  There's not really a single way to guarantee that your chocolate chip cookies come out soft; instead, there are a number of important factors to consider. First of all, consider your baking time and oven temperature.  Over-baked cookies are going to be dry, even if you do everything else right.  And while it's easy to spot a burnt cookie, it's worth noting that you can definitely over-bake before getting to the burnt stage.  Next, consider the moisture content of your cookie.  Now I should note that more moisture in your dough does not guarantee softness! But it is very difficult to make a dry cookie dough turn into a soft cookie.  A wetter dough will also spread more on the cookie tray, meaning that the 'core' of the cookie is smaller and easier to dry out.  This is good if you want crispy cookies, but it adds another challenging dimension if you want them to be soft.  One of the big secrets to cookie softness is actually the addition of an extra egg yolk.  Adding an additional yolk to this recipe will give you a softer, more brownie-like interior, along with a richer taste.  Serious Eats has a really good look at the subject here.

One final note about cookie softness - as written (and in my oven), these cookies turn out crispy on the outside and fairly soft on the inside, but there are a couple of caveats.  First, bake time is important.  My first batch was in the oven for 20 minutes, and while they looked virtually identical to the second 18-minute batch, they were quite a bit dryer.  Second, the softness of the cookies was definitely at its peak on day one.  After about three days, the cookies were definitely getting to the dryer, cakier side of things.  If you're planning to store your cookies for a few days, try to make sure they're in a very well-sealed container.

I cannot stress the importance of good quality chocolate enough. Dark chocolate with a high cacao content is, in my opinion, the only way to go here. I have nothing against a good milk chocolate, but the bittersweet flavour of strong dark chocolate is needed to balance out the toffee/caramel flavours imparted by the brown butter and toasted oats. Overly sweet chocolate will make your cookies taste cloying.

I elected to use large chocolate chunks here, but you can use chips, discs, or chopped chocolate.  All have their own merits.  Chocolate discs or wafers can be a bit tougher to incorporate in a cookie like this because the dough is a bit thicker and less spreading than some chocolate chip cookies, but it's still a good way to go, and can give you somewhat softer, 'meltier' cookies.

Salt is a very, very important part of this recipe. There's a lot of complexity in the flavours, but without salt, many of the sweet notes from the brown butter fall flat. I arrived at 3/4 tsp of salt after playing around a little bit - 1 tsp was great for making the flavours pop, but came across just a touch salty on the aftertaste.

It's important to have salt in the dough itself, but you could also take a note from the famous Bon Appetit brown butter cookie and sprinkle a little sea salt on top of each cookie. This gives you an initial punch of salt that plays beautifully against the dark chocolate, but doesn't make the cookie overly savoury. If you elect to go this route, I would decrease the salt in the dough to 1/2 tsp, then sprinkle a small pinch of flaky sea salt over the cookies before baking them.