adapted from Baked Explorations by Matt Lewis and Renato Poliafito
3/4 cup firmly packed brown sugar
3/4 cup granulated sugar
1 cup unsweetened cocoa powder
1 1/2 cups all-purpose flour
1 1/2 teaspoons baking soda
3/4 teaspoon baking powder
1 teaspoon salt
2 large eggs
1 large egg yolk
3/4 cup buttermilk
1/2 cup vegetable oil
1 teaspoon vanilla extract
6 oz mini chocolate chips
Toss chocolate chips with 1 teaspoon flour and set aside. Spray a 9-by-5 inch loaf pan with nonstick cooking spray. Sift brown sugar, granulated sugar, cocoa, flour, baking soda, baking powder, and salt into mixing bowl. Mix on low for 20 seconds.
In a separate bowl, whisk the eggs and egg yolk until blended, then add the buttermilk, oil, and vanilla; whisk until combined.
Turn the mixer on low and slowly stream the wet ingredients into the dry ones, mixing just until combined.
Stir in the chocolate chips by hand.
Pour the batter into the prepared pan and bake for 1 hour to 1 hour and 10 minutes, or until a toothpick inserted in the center of the loaf comes out clean.
Let the cake cook in the pan for 15 minutes, then turn it out onto a wire rack to cool completely.
The loaf will keep, in an airtight container or wrapped tightly, at room temperature for up to 3 days.
This is amazing as is, or with a scoop of vanilla ice cream!