Marble Bundt Cake

For the cake:
Preheat oven to 350ºF. Butter and flour a 10-cup bundt pan.

In a medium bowl combine flour, baking powder, baking soda and salt. Set aside.

Whisk together sour cream and milk in a liquid measuring cup. Set aside.

Add butter and sugar to a stand mixer with the paddle attachment. Beat until fluffy, lighter in color, and almost white, 3–4 minutes. Add eggs and egg yolk, one at a time, making sure they are fully incorporated before adding the next one. Add vanilla.

On low speed, add 1/3 of the dry ingredients and 1/3 of the milk mixture. Do not over-mix. I like to do the last bit by hand with a rubber spatula. Measure 1 ½ cups of the batter from the bowl and set aside.

Add cooled chocolate to the reserved batter and mix until incorporated. Do not over-mix.

Spoon vanilla cake batter into the prepared pan. Spoon chocolate cake batter on top, avoiding the sides if you can. Using a butter knife, swirl the 2 batters together in an S-shape motion.

Place in the oven and bake for 35–40 minutes, or until a toothpick inserted comes out clean. Allow to cool in the pan for 20 minutes then invert on to a wire rack to cool completely.

Serve plain or dust with cocoa powder, powered sugar or (my favorite) chocolate ganache. Store cake in an airtight container at room temperature for up to 3 days.

For the chocolate ganache:
Add chocolate chips and heavy cream to a medium microwave safe bowl. Heat in 15-second intervals until fully melted.

Allow the ganache to cool for about 2–3 minutes. Pour and spread on top of the cake. Place back into the fridge to allow the ganache to set.