Preheat the oven to 350 F. Prepare 2, 8 x 4″ loaf pans with cooking spray, then line with parchment paper, set aside.

Prepare the basic batter. Beat the butter and the sugars with an electric mixer on medium speed, or in the bowl of a stand mixer fitted with a paddle attachment, until light and fluffy, about 4 minutes.

Add the eggs and egg yolks one at a time, beatuing on medium-low after each addition. Add vanilla and beat until just incorporated.

In a medium bowl whisk together the flour, baking powder, and salt. Add to the butter mixture, alternate with the sour cream. Begin and end wit the flour mixture. Beat on low speed until just combined after each addition.

Divide the Basic Batter into 2 medium bowls.

Prepare the Pumpkin Batter

Add flour, canned pumpkin and pumpkin spice to 1 bowl of the basic batter, stir together until completely combined. Set aside.

Prepare the Chocolate Batter

Add cocoa powder, sour cream and instant coffee granules to the remaining bowl of basic batter, stir until combined and smooth.

Drop large spoonfuls of the pumpkin spice batter across the bottom of the 2 prepared loaf pan, Then drop large spoonfuls of the chocolate batter into the pans, be sure to intersperse it with the pumpkin bread batter. Repeat with another layer of pumpkin batter, then chocolate cake batter until all of the batter is used.

Using a skewer or a butter knife swirl the batters moving back and forth from one side of the pan to the other to make the marbled effect.

Bake the pumpkin chocolate marble loaf in the preheated oven about 55-60 minutes. Or until a wooded toothpick inserted into the center of the loaves comes out clean. Remove pans from oven, cool on wire rack for 15 minutes, turn out bread to cool completely for about 45 minutes.