Chocolate donut cake is a rich, moist and tender chocolate cake shaped like an oversized old fashioned chocolate cake donut. Top with this chocolate cake donut with vanilla glaze.
In a large bowl, whisk the flour, Dutch processed cocoa powder, baking powder, baking soda, salt nutmeg or cardamom and instant espresso powder together until well combined.
In the bowl of a stand mixer fitted with paddle attachment, cream the butter, sugar and light brown sugar together until light, fluffy and well combined. This takes about 2 - 3 minutes at medium speed. Scrape the sides and bottom of the mixing bowl.
By hand or on the lowest mixing speed, mix the dry ingredients into the wet alternating with the buttermilk and sour cream until the batter is just combined. Gently stir in the hot water until well mixed into the chocolate cake batter.Evenly scoop the chocolate donut cake batter into the prepared bundt pan.
Cool the cake in the pan for 10 minutes. Invert the bundt cake pan onto another cooling rack or plate. Then flip the cake upside down one more time so the top is facing up again. Cool the cake completely before topping or serving. Bake the donut chocolate cake for 45 - 50 minutes or until a toothpick inserted into the center of the pound cake comes out with a few moist crumbs.
Make the vanilla glaze by whisking the powdered sugar with water or coffee, milk and vanilla extract.Pour the glaze on top of the cooled cake donut. Use a pastry brush to apply the glaze to the sides of the cake. Allow 30 - 45 minutes for the glaze to fully set, slice and enjoy.