Marble Bundt Cake

1. Preheat to 325F (165C). Properly grease and flour a 10 cup bundt pan.
2. In a medium mixing bowl, add cocoa powder and hot water/coffee. Mix ingredients together until a smooth but thick chocolate paste is achieved. Set aside.
3. In a separate medium mixing bowl, add the flour, baking powder, baking soda and salt. Lightly whisk to combine.
4. In a standard measuring cup or small bowl, add and whisk together the yogurt, milk and vanilla extract.
5. Add the butter, oil and sugar into the bowl of a stand mixer fitted with paddle attachment.  Cream ingredients at medium speed (4 on stand mixer) until mixture is fluffy and pale yellow in appearance, about 3-4 minutes.
6. Beat eggs into batter one at a time allowing the previous egg to be fully incorporated into batter before adding the next egg.
7. Reduce mixer speed to low (2 on stand mixer). Mix in half of the dry ingredients into batter followed by the yogurt mixture and ending with the remaining dry ingredients.
8. Using a flexible spatula, scrape the sides and bottom of mixing bowl to catch any unmixed ingredients. Resume mixing cake batter at low speed for an additional minute.
9. Spoon 1 cup of the vanilla cake batter into bowl with chocolate mixture and mix to thoroughly combine.
10. Spoon half of the remaining vanilla cake batter into prepared bundt pan, followed by all of the chocolate cake batter and ending with the rest of the vanilla cake batter.
11. Use a skewer/butter knife to swirl chocolate cake batter into the vanilla cake batter.
12. Place bundt pan onto a baking sheet and bake marble bundt cake batter for 60 minutes rotating the pan halfway through bake time. Cake is ready when a toothpick inserted into the center comes out clean.
13. Allow marble bundt cake to rest in pan for 10-15 minutes before inverting onto a cooling rack to cool completely to room temperature, about 40-60 minutes.

Chocolate Ganache Glaze

1. Warm heavy cream either on stovetop or microwave at 30 second intervals just until hot but not boiling.
2. Add finely chopped chocolate into a medium mixing bowl and pour warmed heavy cream over the top. Allow mixture to sit untouched for at least 30 seconds.
3. Whisk heavy cream into chopped chocolate starting inward and moving outward. Continue to whisk mixture until all the chocolate is melted. Chocolate ganache should be smooth and shiny without any lumps of chocolate.

Assembly

1. Transfer cooled marble bundt cake to serving platter.
2. Pour chocolate ganache glaze over bundt cake.
3. Slice marble bundt cake into equal slices and serve.