Instructions

• Preheat the oven to 350°F and place a rack in the center. Lightly grease a 9x5-inch loaf pan with a small amount of the 1/2 cup vegetable oil, then dust the pan with all-purpose flour and tap out the excess.
• Put the 3/4 cup firmly packed dark brown sugar into the bowl of a stand mixer fitted with the paddle attachment. Press out any lumps with the back of a spoon.
• Sift the 1 cup dark unsweetened cocoa powder directly into the mixer bowl. Add the 1 1/2 cups all-purpose flour, 3/4 cup granulated sugar, 1 1/2 teaspoons baking soda, 3/4 teaspoon baking powder, and 1 teaspoon salt. Mix on low just until the dry ingredients are evenly distributed, then scrape down the sides and bottom of the bowl.
• In a separate bowl, whisk the 2 large eggs and 1 large egg yolk until blended. Add the 3/4 cup buttermilk, the remaining 1/2 cup vegetable oil, and 1 teaspoon pure vanilla extract; whisk until combined.
• With the mixer running on low speed, slowly stream the wet mixture into the dry mixture. Mix only until the batter is just combined and no large streaks of flour remain—do not overmix.
• Using a spatula, fold in the 8 ounces coarsely chopped dark chocolate (60–72%) by hand until evenly distributed.
• Pour the batter into the prepared loaf pan and smooth the top with a spatula.
• Bake for 1 hour to 1 hour and 10 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
• Let the loaf cool in the pan on a wire rack for 15 minutes. Run a knife around the edges, invert the loaf onto the rack, and let it cool completely.
• Slice and serve with whipped cream and strawberries, if desired.