Add flour, baking powder, baking soda, instant espresso, and any other dries if using substitutions, to the egg mixture. Whisk until completely combined. Add food color to desired shade. Switch to a spatula to blend it in if whisking is too difficult (Dough should resemble an extra thick batter. If you feel it’s a little too runny, add 1 tbl of flour or cocoa powder to stiffen up.)