The Science of Cookies

Under lockdown, I’ve had a lot of time to pursue things I might not have in the past. Quarantine gave me a chance to start my cookie science experiment. On the 13th of January, 2020, long before the world changed, I baked what would become the first test for this experiment. With a global pandemic, I’ve now had five total months to work towards the best classic chocolate chip cookies. I want to make it clear that when I say "classic," that's exactly what I mean. A simple cookie with chocolate chunks. My cookies only ever had toppings that were chocolate. No raisins, oats, M&Ms, cranberries, pretzels, or any other add in you can think of.
Along the way, I have learned so many things by slightly tweaking my recipe with each new batch. I have probably made over fifteen batches of cookies since that first one. I wouldn't have been as dedicated to this project if I weren't quarantined. One thing I learned is that it's nearly impossible to make the exact same cookie twice. 

The first batch was not bad. It was the original Nestle Toll House recipe. I wouldn't call them my cookies because I didn't contribute anything other than putting them together and in the oven. The Nestle Toll House recipe was simple and tasty, but after a few batches, I wanted a challenge. I wanted to call the cookies my own.

This leads us to the 13th of April. This is when I adopted Bon Appétit's chocolate chip cookie recipe and things got serious because I was pretty sure the lockdown wasn’t ending anytime soon. The first batch I made with this recipe was probably the best. The shape of the cookies were nearly perfect, the color was spot on, the texture was amazing, and they were overall beautiful cookies.

This recipe was completely different from Nestle Toll House's recipe. Bon Appétit's recipe had browned butter, something I didn't know about until this experiment. It also called for one whole egg and two egg yolks. Why we couldn't just use two eggs, I didn't know (I later learned that the egg yolks contained the fat in the egg which made the cookies chewier). The point is, this new recipe was strange to me. I came to love the things that were different about the recipe and quickly understood their importance in the cookies. I also learned about all the possible variables. Below, you’ll see my approach to:
  1. Measuring
  2. Butter
  3. Sugar
  4. Baking


Dark cookies
Although it doesn't seem necessary, the best way to measure in the kitchen (not just for cookies) is to weigh everything. As long as the recipe has the measurements in grams or ounces, it's a fool-proof way to be accurate. I recently made the mistake of using cups to portion out the brown sugar instead of grams. I ended up with cookies that were way too sweet, dark, and they were overall, bad cookies.


When picking a butter for your cookies, it is vital that it be unsalted. Unfortunately, I made the mistake of using salted butter in some early batches and ended up with very salty cookies. This is because we do not know how much salt is in the butter and different types of salted butter have different amounts of salt in them.

One thing the “Bon Appétit” recipe does is brown their butter. Browning butter is done by slowly melting butter over a flame until it becomes dark brown. This gives the cookie a caramel taste which I have found to be very good. Not only do they brown their butter but they leave a small portion of the butter unmelted. When the larger portion of butter is browned, it is poured over the solid butter to melt it. This is something I still don't completely understand. I assume it is because the completely browned butter would be too strong so the normal butter is there to dilute it in a way. Of course, the melted butter makes the cookies much more fluid and difficult to manage, but they end up having a beautiful caramel taste to them so I think it's worth the hassle. Browning the butter is not necessary if you do not want a slight caramel taste.


The sugar proportions have been something I have struggled with since the beginning. Now I think I understand more about about sugar but I am still learning. There are four different types of sugars to choose from: white sugar, light brown sugar, brown sugar, and dark brown sugar. It's difficult to find normal brown sugar as described in US recipes here in Italy, but I have no problem finding the other three. The original Bon Appétit recipe calls for 50 grams of white sugar and 200 grams of dark brown sugar but I found the caramel flavor to be too strong when paired with brown butter. Now I use 50 grams of white sugar, 100 grams of light brown sugar, and 100 grams of dark brown sugar. These still have a caramel taste to them but much less than the previous batches. 

I’ve learned that the reason any type of brown sugar is included in cookies is because it contains molasses which adds moisture to the cookies and extends their shelf life. Contrary to what you may think, the equal mixture of light and dark brown sugar does not balance to be the equivalent of normal brown sugar as the dark brown sugar is much stronger. The addition of light brown sugar in the place of half of the dark brown sugar simply acts as a type of diluent without throwing off the texture or consistency of the batter. 

In future batches, I might consider increasing the amount of light brown sugar and decreasing the amount of dark brown sugar. This is because I am still concerned that the caramel flavor is slightly too overpowering and is taking away from some other aspects of the cookie. 


As mentioned earlier, I use brown butter in my cookies which is basically just fancy melted butter. This causes the batter to be much softer and it can be difficult to handle. A simple way to fix this is to put your batter in the fridge for at least an hour. This makes the cookie dough much easier to manage. Not only that, but it also makes everything the same temperature which allows all parts of the cookies to bake evenly. 

Flat cookies It is important that the oven be very hot when you put in your cookies. If the oven isn't hot enough, the cookies could become flat and thin. The batch to the right is the result of an oven that was too cool. The cookies melted instead of baked. They tasted the same but their texture was boring and they were too flat for my liking. This is simply because it wasn't hot enough to reach the inside of the cookie. The outer layer melted just enough for the next inner layer to start baking and the process repeated. The cookies didn't bake properly and that ruined a perfectly good batch of cookie dough.

When baking cookies it's important to bake them on parchment paper. I found that when I used a non-stick baking sheet my cookies were very oily on the bottom and had a slight taste to them that wasn't there when I used parchment paper. 

When cooling cookies, I usually let them cool on the baking pan and don't touch them for a little while. This allows the bottom of the cookies to become a bit more crispy while the rest of the cookie cools down. It also stops me from accidentally moving them too soon and breaking them in the process. This is one of the reasons I avoid using cooling racks; if the cookies are not fully set and are placed on cooling racks, they will droop in the middle or possibly break. 


In conclusion, the perfect classic chocolate chip cookie recipe does not yet exist. At least, not for me it doesn't. Cookies are something we all have different opinions about. Some people like their cookies crispy, and some like them chewy. Some like their cookies thick while others like them thin. The perfect cookie exists in my mind and I think I'm getting closer with each batch, but until I find it, it's not so bad having two dozen cookies each week. 

While quarantine isn’t the ideal way to go about things, I wouldn't have even attempted to find the perfect recipe if I wasn't for life under lockdown. Like I said in my previous blog, we need to find new ways to entertain ourselves while quarantined and I like to think I’ve brought a bit of the classic American cookie to my new home of Italy. This new form of entertainment has truly been a journey and even though I haven't found the perfect chocolate chip cookie recipe yet, I enjoyed learning about this new and unusual topic.

For a look at my current working recipe see below. Just know it’s still evolving:
  • 200g flour
  • 4g salt
  • 4g baking soda
  • 113g unsalted brown butter
  • 56g unsalted butter
  • 50g white granulated sugar
  • 100g light brown sugar
  • 100g dark brown sugar
  • 1 egg
  • 2 egg yolks
  • 2 tsp vanilla extract
  • 100g (1 bar) milk chocolate
  • 100g (1 bar) dark chocolate

  1. Mix together the flour, salt, and baking powder in a medium bowl. Set aside
  2. To make the brown butter: take 113 grams of unsalted butter and melt it over low heat. Stir constantly while scraping the bottom of the pot until melted butter turns brown. 
  3. Once butter is browned, pour over small cubes of unsalted butter and allow everything to melt together. Mix.
  4. Add white, light brown, and dark brown sugar into the butter mixture. Whisk until evenly mixed.
  5. Add egg and egg yolks to the butter and sugar mixture. Whisk until smooth. 
  6. Add vanilla extract and mix. 
  7. Add in about a quarter of the flour, salt, and baking soda mixture. Repeat until all of the dry mixture has been thoroughly incorporated to the batter and there are no lumps.
  8. Roughly chop the bars of chocolate and mix them into the batter.
  9. Preheat the oven to 190º C (375º F)
  10. Refrigerate for one hour.
  11. Line baking pans with parchment paper.
  12. Make balls of dough roughly three centimeters in diameter. Place on a baking sheet evenly spaced.
  13. Bake for 7-10 minutes.
  14. Let cool on baking pans for at least 10 minutes. Enjoy!


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