Preheat oven to 350°F (175°C) and line a 9×13-inch pan.
Whisk flour, cocoa, baking powder, baking soda, and salt.
Beat until fluffy; add eggs and vanilla.
Alternate adding dry ingredients with buttermilk; stir in hot water.
Pour batter into pan and bake 25–30 minutes.
Whip cream cheese, cream, sugar, and vanilla.
Add pink coloring to coconut.
Layer cream and coconut on cooled cake.
Refrigerate for 1 hour before slicing.
