The Protein Cookie Experiment
Leo Biette-TimmonsShare
How Much Protein Can You Add To A Cookie?

If you're a protein connoisseur like I am, I'm sure you've been burned by gross, crumbly "high protein cookies" before.
Most protein cookie recipes fail because they don’t account for structural balance. In a traditional cookie, structure primarily comes from:
- Flour starch (framework)
- Egg proteins
- Sugar crystallization (crisp exterior)
- Fat dispersion
In this experiment, I replaced different amounts of flour with a 1:1 whey-casein blend.
This experiment increases protein contribution stepwise:
- Control (baseline protein presence +22%)
- +34%
- +44%
- +60%
Below are all four recipes, each making 8 cookies. Nutrition and macronutrient information will follow each ingredient list. If you follow the exact recipe, you'll see I used 25g of egg (which is half an egg). My recommendation is to crack an egg, whisk it up, and pour 25g into your batter.
The protein powder I use is a vanilla whey & casein, both from Levels. I use their protein in every recipe, creamis, and the odd shake (I hardly ever drink my protein anymore). Great taste, good macros, I highly recommend it.
The +22%, +36%, and +46% cookies all get baked at 375°F for 9.5 minutes on the dot. The +60% get baked at 350°F for 10 minutes. Over baking the +60% will dry them out.
Ingredients
Control +22%

- 56g room temp butter (half stick)
- 58g sugar
- 53g brown sugar
- 1/2 tsp vanilla
- 25g egg
- 80g all purpose flour
- 11g whey
- 11g casein
- 75g chocolate chips
- 15g 0% Greek yogurt
- 1/4 tsp baking soda
- 1/8 tsp baking powder
- Pinch salt
Here, the flour still dominates, with the protein powders acting as minor structural modifiers, not primary builders.
The cookie behaves like a classic chocolate chip cookie: Good spread, soft center, light chew, classic crumb
Nutrition (Per Cookie – 1 of 8)
- Calories: 205
- Protein: 4g
- Carbs: 28g
- Fat: 9g
36% Protein Increase

- 56g room temp butter (half stick)
- 58g sugar
- 53g brown sugar
- 1/2 tsp vanilla
- 25g egg
- 65g all purpose flour
- 17g whey
- 17g casein
- 75g chocolate chips
- 20g 0% Greek yogurt
- 1/4 tsp baking soda
- 1/8 tsp baking powder
- Pinch salt
Very similar cookie with a slightly firmer chew, less "melt in your mouth." The yogurt compensates with extra hydration.
Nutrition (Per Cookie)
- Calories: 204
- Protein: 5g
- Carbs: 26g
- Fat: 9g
46% Protein Increase

- 56g room temp butter (half stick)
- 58g sugar
- 53g brown sugar
- 1/2 tsp vanilla
- 25g egg
- 55g all purpose flour
- 22g whey
- 22g casein
- 75g chocolate chips
- 25g 0% Greek yogurt
- 5g skim milk
- 1/4 tsp baking soda
- 1/8 tsp baking powder
- Pinch salt
This dough is slightly softer and more pliable since there's less gluten structure. The cookies rise a bit more, and have a slightly fluffier texture.
Nutrition (Per Cookie)
- Calories: 205
- Protein: 6g
- Carbs: 26g
- Fat: 9g
60% Protein Increase

- 56g room temp butter (half stick)
- 58g sugar
- 53g brown sugar
- 1/2 tsp vanilla
- 25g egg
- 40g all purpose flour
- 30g whey
- 30g casein
- 75g chocolate chips
- 30g 0% Greek yogurt
- 5g melted butter
- 1/4 tsp baking soda
- 1/8 tsp baking powder
- Pinch salt
You'd think these cookies would be dry protein pucks, you'd also be wrong. As was I. Added butter compensates for lost tenderness. They're almost indistinguishable from the +46%.
Nutrition (Per Cookie)
- Calories: 210
- Protein: 8g
- Carbs: 24g
- Fat: 10g
100% Protein Increase

- 56g room temp butter (half stick)
- 58g sugar
- 53g brown sugar
- 1/2 tsp vanilla
- 25g egg
- 50g whey
- 50g casein
- 75g chocolate chips
- 40g 0% Greek yogurt
- 10g melted butter
- 1/4 tsp baking soda
- 1/8 tsp baking powder
- Pinch salt
Nutrition (Per Cookie)
- Calories: 198
- Protein: 11g
- Carbs: 16g
- Fat: 11g
To be completely honest, I thought these would suck. To my surprise, they did not. The texture is pretty damn good. A crisp exterior overshadows a slightly gummy interior, they light and soft. The only issue is they have a protein powdery aftertaste.
Recipe
-
Preheat oven to 375°F and line a baking sheet with parchment paper.
- If baking the +60%, preheat oven to 350°F.
- If baking the +100%, preheat to 325°F.
- In a bowl, cream softened butter with your sugar until light and fluffy.
-
To the creamed sugar, add in vanilla, egg, and Greek yogurt until smooth.
- To the +46%, this is when you add in your milk.
- To the +60% and +100%, this is when you add in the melted butter.
- In a separate bowl, whisk together flour, whey, casein, baking soda, baking powder, and salt.
- Add dry ingredients into wet and mix until just combined. Fold in chocolate chips.
- Refrigerate for a minimum for 30 minutes.
- When ready to bake, divide the dough into 8 equal balls. Slightly flatten the tops.
-
Bake the +22%, +36%, +46% for 9.5 minutes on the dot.
- Bake +60% for 10 minutes.
- Bake +100% for 12 minutes.
- Once out of the oven, let rest on the pan for 5–10 minutes before transferring to a rack. They’ll firm up as they cool.