Friday, November 29, 2019

Science with Chocolate Chip Cookies

Step 1: Define the result of a successful experiment. In this case, I sought a chocolate chip cookie that was delicious and oh-so-soft.

Step 2: Do background research. Wow, this was fun! Most of my old links were dead, but here's a fantastic new crop (including some of the same information at new homes):

Are you hungry now? I couldn't wait to get started!

Step 3: Based on your research, create a likely plan. I selected these ingredients for their characteristics:

  • margarine, creamed from the refrigerator (creamed for cakier cookies, lighter and firmer; warmer butter yields denser cookies)
  • brown (tall and moist) and white (thin and crisp) sugars, with some syrup
  • more flour (cake flour for softer cookies)
  • chill dough 24hr (to elevate flavor; cool dough for compact cookies with less spread)
I'm lactose-intolerant, so margarine is less likely to cause me digestive issues later; I often say "butter" and mean "butter or margarine, probably margarine if I'm eating it". The recipe I selected as a starting point is The Ultimate Healthy Soft & Chewy Chocolate Chip Cookies from Amy's Healthy Baking because softness was a key goal for that recipe too. Aside: I am never going to call chocolate chip cookies healthy, but some recipes are less bad than others.

Detour: One chocolate chip cookie recipe that is less unhealthy that my Very Picky Eater actually loves is for Pumpkin Chocolate Chip Cookies from The Candid Appetite. However, since I always modify recipes, I made that recipe, but with fresh sweet potato purée instead of fresh pumpkin purée (other substitutions would include butternut squash, actually in many cans of "pumpkin pie filling"), and skipping the nutmeg and allspice and walnuts because I know my audience. However, based on my experience, I recommend that you do not use purple sweet potatoes because the cookies were an unappetizing shade of blue-green on the inside! The color initially made me think of copper sulfate (not anhydrous), and I don't want my food to look like that! Luckily, the cookies were delicious and we ate them all ... while laughing about how terrible they looked.

Another Detour: My Very Picky Eater also loves these Chocolate Chip Chocolate Zucchini Cookies. Again, since I always modify recipes, I use zucchini purée (I also drain off some of the liquid, so the purée is slightly thicker - more like wet batter) because shredded zucchini was a notable texture (picky eaters and unexpected textures do not mix happily), with no cinnamon or walnuts (because I know my target audience). I'm not going to lie to my children "just because it's easier" so for both of these recipes, my picky eater knows that I put vegetables in his cookies and he still loves them.

Step 4: Experiment! Did you think I would start my science at this step? No, I know the value of careful planning! There were many batches of chocolate chip cookies, and a winner emerged that best fit the criteria for success.

Step 5: Document and publish your results for other scientists to verify. OK, here goes!

Yield: 34 cookies

Preparation Time: 20 minutes

Total Time: minimum 4 hours and 40 minutes


  • 2 cups all-purpose flour (measured correctly with no compression)
  • 1/2 Tbs aluminum-free baking powder
  • 1 Tbs clear gel, or 1/2 Tbs arrowroot powder
  • 1/4 tsp salt
  • 6 Tbs butter, melted (I was persuaded / asked nicely to use butter instead)
  • 1 egg, at room temperature
  • 1 Tbs skim milk
  • 4 tsp vanilla extract
  • 1 cup brown sugar
  • 1/4 cup chocolate chips
  • 2 Tbs mini chocolate chips, divided


  1. On a flexible sheet, sift together the flour, baking powder, cornstarch, and salt. In a bowl, whisk together the melted butter and egg until fluffy. Whisk in the milk and vanilla extract. Stir in the brown sugar, smearing out any clumps along the side of the bowl. Add in the flour mixture, stirring just until incorporated. Fold in the regular chocolate chips and 1 tablespoon of mini chocolate chips.
  2. Cover the top of the bowl with plastic wrap, and chill in the refrigerator for at least 4 hours, up to 24 hours.
  3. Preheat the oven to 350°F. Roll the chilled cookie dough into 24 balls, and place on the prepared baking sheets. Make sure each cookie has visible chocolate chips, pressing more into the top of each as needed. Flatten slightly to about 3/4-inch thick. Bake at 350°F for 10-12 minutes. Remove from the oven and allow the cookies to sit on the warm baking sheet for 10 minutes before turning out onto a wire rack.

Recipe Notes:

  • Do NOT overbake these cookies! After 10-12 minutes in the oven, they’ll still look and feel slightly underdone, but they’ll continue to bake and set on the warm baking sheet for the 10 minutes after. Remember: these cookies should be soft!
  • Second batch should be in for less time (first batch was fine at 11 minutes, but second batch was crispier).
  • Cornstarch has a (faint) bitter flavor in this recipe, so use gel (best) or arrowroot powder instead. This ingredient adds softness and thickness.
  • Other scientific notes from the original base recipes:
    • less butter, and melted for chewiness
    • more vanilla for buttery flavor
    • brown sugar for moisture and chew
    • regular and mini chips for more chocolate throughout
    • chilling for thickness
    • baking 10-12 minutes for softness

Equipment: cookie scoop, cookie sheet, measuring, mixing bowl, oven, refrigerator