In a bowl, mix dry ingredients (flour, cocoa powder, baking soda, and salt)

In another bowl, whisk together softened butter, brown sugar, and caster sugar till combined. Add eggs, one at a time, vanilla, and food coloring and whisk until homogeneous.

Add dry ingredients and mix till all combined.

Put in fridge for at least 4 hours.

Preheat oven 180c

Scoop little balls from the dough, coat with caster sugar, then powder sugar.

Bake for 12 minutes. Let it cool before serving.