Cookie Lab: Making the Perfect Chocolate Chip Cookie

Cookie Lab: Making the Perfect Chocolate Chip Cookie

Chocolate chip cookies are classic. While the fancy stuff is good, a chocolate chip cookie almost never disappoints. I wanted to set out to develop own recipe and decided to start with the fan favorite cookie. This is the process that I went through to develop the recipe for my perfect chocolate chip cookie.

what makes up a perfect chocolate chip cookie?

  • Gooey chocolate
  • Crisp outside
  • Soft inside
  • Chewy

The anatomy of a chocolate chip cookie

An interactive ingredient breakdown

Click on each image to see more information about what each ingredient contributes.


  • main source of water in a cookie
  • adds fat and protein
  • extra egg yolk = adds additional chew to the cookie


  • can't have a chocolate chip cookie without it
  • deliciousness

Granulated Sugar

  • encourages spreading
  • browns the cookies
  • absorbs moisture in the dough


  • contributes to gluten development
  • adds structure to the cookie


  • adds buttery flavor
  • prevents gluten development

Baking Soda

  • encourages browning
  • neutralizes acidity
  • contributes to rise of cookie

Brown Sugar

  • adds flavor
  • contributes to chewiness


  • flavor enhancer
  • combats sweetness


  • adds flavor






Baking Soda


Brown Sugar


starting ratios

I started out the recipe with a lot of research. I consulted lots of different recipes out there, looking for similarities and differences in their ingredient ratios. The most useful source that I used was from Pancake Princess, who not only tested 12 different recipes and got input from 30 tasters in two different age groups, but also has a really great breakdown of the recipe ratios all compared in some beautiful interactive graphics. Looking at the breakdown helped give me a general understanding for the relative amount of each ingredient that should be included in a chocolate chip cookie.

At this stage I determined the bake temperature, a starting recipe and some ideas with what I wanted to experiment with. 

step one: butter

There are two main methods for working with the butter: melted and creamed butter. Melted butter has no air incorporated into it, leading to a denser and flatter cookie. On the other hand, creamed butter, which has been whipped, has air incorporated into it, making for a thicker more cakey cookie. 

In addition, a relatively new technique of browning the butter before adding it to the dough to give the cookies more nuttiness and a more complex flavor has gained popularity. Brown butter (aka Beurre noisette in French if you want to be fancy) is butter that is heated so that the milk solids separate from the butter fat and toast off. This leads in a change of color and a toasty aroma.

COOKIE SCIENCE: Browned butter or beurre noisette is heated so the milk solids separate from the butter fat and toast off.

When I did my first test with creamed butter, there was nothing wrong with the cookie, but it just felt like it was lacking flavor. While it tasted like a chocolate chip cookie, it tasted very basic. When I tested it with the browned butter I could immediately taste that it was better. The flavor was more intense and less two-dimensional.

browned butter vs creamed butter

step two: thickness

I'm a fan of a heftier cookie so I like it to have a bit of height to it. The initial tests that I did yielded some pretty nice looking cookies but they were about as thick as those grocery store chocolate chip cookies and I wanted something a bit taller.

comparison of browned butter versus creamed butter
Left to right: all creamed softened butter, half warm browned butter and half regular softened butter, all warm browned butter (side note: the creamed butter also had one less egg yolk than the other two variations)

Because of that, I decided to let the butter cool completely to room temperature after browning rather than working with the melted butter. This results in the dough being at a lower temperature when it goes into the oven so the cookies spread a bit slower. It also allowed me to cream the butter and incorporate some air into the dough to contribute to a thicker cookie. The downside of this is that it takes a bit longer since you need to wait for the butter to cool, but it yielded exactly the results that I wanted.

step three: texture

While the browned butter created a deeper depth of flavor, it wouldn't account for the texture. The cookie was missing richness. To address this, I added an extra egg yolk for a more fudgy and rich texture.

In addition, one thing to note about using browned butter is that the butter cannot reach a temperature hot enough for the milk solids to brown until all the water has evaporated off. This means that the browned butter adds virtually no moisture to the dough. When I used cooled browned butter without additional liquid, the cookie dough was crumbly and there was barely any spread during baking. Furthermore, the cookies browned faster which resulted in a more raw interior that had the distinct texture of undissolved sugar while having a contrastingly crisp exterior. However, I did really like that it maintained its thickness and it had a visually pleasing look.

COOKIE SCIENCE: Butter contains roughly 15% water. However, the butter cannot get hot enough to brown until the water evaporates so browned butter adds virtually no moisture.

The reason that the sugar didn't dissolve is because sugar molecules are hydrophilic. This means that they dissolve in water, not fat. Therefore there wasn't enough water in the cookies for the sugar to dissolve since the only source of water in the cookie was coming from a single egg white.

Since I wasn't a big fan of the taste of undissolved sugar, I tried adding water to combat the water displacement due to browning the butter. The result was a significantly larger spread of the cookie and a more cakey texture. Since there seemed to be a bit too much liquid at this point I then added a bit of extra flour to help absorb that liquid and give the cookie a bit more structure. The result was something in-between the last two trials in terms of spread and structure. It tasted like the first version but without the taste of the undissolved sugar and a bit less of a raw taste.

recipe variations

step four: the look

I saw a method for getting more craggy cookies in a recipe from Binging with Babish and decided to try it out on some of the cookies. It's essentially making a dough ball and then ripping off some dough from the top of it and sticking it back on. This makes for more irregularity in the dough ball. As you can see in the photos, the recipe version with just cooled browned butter (no extra water or extra flour) and the version with cooled browned butter, extra water, and extra flour maintained large differences in appearance with this method.

tearing method
versions made with cooled browned butter

versions made with cooled browned butter, extra water, and extra flour

I like the look of the cookies with the tearing method because they look a lot more homemade. The cookies with the cookie scoop do still have the crinkles but they're a lot more consistent. The tearing method makes for the cookies to have more irregularities which makes for a nice mix of some crispier bites and some softer bites and also just having an overall more attractive appearance.

step five: chilling

One big tip that is often brought up when making chocolate chip cookies is refrigerating the dough. Chilling the dough supposedly makes the cookies more flavorful and darker in color by concentrating the flavor and drying out the dough to control spread.

I tested at 3 intervals: no chilling, one hour, and twenty four hours. The 24 hour chilling maintained the most structure, meaning that they most closely resembled the shape that the dough was initially in prior to the bake. However, all three ended up very similar visually. As for taste, there were minor differences. The less chilling that there was, the more buttery the cookie tasted, meaning that the distinct flavor of butter was at the forefront. With more chilling, the flavors were more balanced with less of the distinctiveness of the butter flavor. The chilled cookies also browned a bit faster, the 24 hour chilled cookies were taken out of the oven about 30 seconds before the ones with no chilling.

chilling of the cookie dough comparison test
Left to right: no chilling, 1 hour of chilling, and 24 hours of chilling

While there were some differences, I would say that overall it's not really worth it to chill the dough (at least for this specific recipe) because the changes are so minuscule that you wouldn't really notice. Given the amount of extra effort that chilling requires, I don't think that the difference is large enough that I would recommend chilling the dough. 

the final recipe

Click here to view the final recipe.

research resources on the science of chocolate chip cookies


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