• Prepare a 9" or 10" Bundt pan by generously spraying the inside with non-stick baking spray or melted butter. Lightly dust with flour.

Filling

• Combine brown sugar, espresso powder and chocolate chips in a bowl. Set aside.

Cake Batter

• Preheat oven to 325°.
• Combine eggs, yolks and sour cream in a small bowl and mix to combine.
• Add sugar, flour, baking powder and baking soda in the bowl of a stand mixer fitted with the paddle attachment. Combine ingredients. Note: a hand mixer may also be used.
• Add softened butter and mix on low speed for 3 minutes.
• Add half of the egg/sour cream mixture to the mixing bowl and combine on low speed for one minute. Scrap sides of bowl.
• Add remaining egg/sour cream mixture to the mixing bowl and combine on low speed for one minute. Scrape sides of bowl and mix on low speed for another minute.
• Add ½ of the cake batter to the prepared pan and smooth with a rubber spatula.
• Scatter the chocolate/espresso/brown sugar mixture on top of the batter in the Bundt pan. Add the remaining batter and smooth with a rubber spatula.
• Bake for 50 minutes at 325° or until top is quite brown and a toothpick inserted in the center comes out clean.
• Remove pan from oven and cool upright for 10 minutes.
• Flip pan upside down onto a cooling rack and let cool completely. Remove pan - cake should release from pan on its own. If not, use blunt knife and gently loosen sides.

Coffee Drizzle

• Mix the confectioners' sugar and espresso together and drizzle over cake.