Make a chocolate Cake I want to alter this recipe to make a chocolate cake. 

3/4 cup butter
1 cup granulated sugar
4 eggs
1 tsp of vanilla extract
1/4 tsp of almond extract
1 1/2 cups of almond flour
1/2 cup of coconut flour
2 tsp baking powder
1/4 tsp sea salt


If I add 1/3 cup cocoa to this Almond cake recipe, what else do I have to change, if anything? Will that amount of cocoa change the batter in a way I have to compensate for?
Yes, that amount of cocoa will change the batter. It will make the cake drier. 

The more cocoa powder you add the more sugar and moisture you will need to prevent the cake from getting dry.

I would take out a 1/4 cup of the almond flour and add a 1/4 cup of cocoa powder. If you feel you would like a little more go buy a tablespoon at a time after that.