Preheat the oven to 350 degrees F (175 degrees C). Grease a fluted tube pan (such as Bundt) with cooking spray.
Mix cocoa powder and hot coffee together in a bowl until cocoa is fully dissolved. Whisk in milk to thin and cool mixture.
Stir flour, salt, and baking powder together in a bowl.
Cream sugar, butter, and cream cheese in a bowl with an electric mixer until white and fluffy (like frosting), about 5 minutes. Mix in vanilla. Add eggs and egg yolks, one at a time, mixing completely after each addition. Mix in 1/2 of the flour mixture until incorporated. Stir in cocoa-milk mixture, then mix in remaining flour mixture until well blended. Pour batter into the prepared pan.
Bake in the preheated oven until a toothpick inserted into a few places comes out dry, 70 to 90 minutes.