How to adjust Baker's Percentage when Adding Ingredients I have a recipe of Old Fashioned Donuts that I love... I would like to add some Cocoa Powder to the recipe, but I don't know how to do that and keep the percentages correct. Basically, I don't know if adding Cocoa Powder will muck up the percentages the same as say adding more flour. 

The Current Recipe is as follows:


600 g Flour 
12 g Kosher Salt 
90 g Egg Yolk 
30 g Unsalted Butter 
15 g Baking Powder 
380 g Sour Cream


As a bonus... how much cocoa powder for a recipe like this would be appropriate? I'm kind of new to baking.
Cocoa powder is a drying agent. So you would want to remove a portion of the flour, and replace with a smaller portion of the cocoa powder plus an extra pinch of baking soda to counteract the acid nature of cocoa powder.

So if you were to follow the advice of 480g flour and 120g cocoa powder, (which sounds good) I would add a 1/4tsp of baking soda in addition to the baking powder.

I would try that out, keeping in mind that cocoa in addition to being acidic acts as a drying agent and so you may find that the above suggestion yields a slightly dryer donut than the original recipe. Adjust incrementally by tbsp of milk.

As a side note, we've all had fried chocolate donuts before and they probably haven't been bitter or burnt tasting. If you use way too much cocoa, sure. Creating recipes can be tricky, keep in mind it often takes some experimentation to perfect.