Chocolate Bundt Cake

INGREDIENTS

• 2 1/2 cups all-purpose flour
• 1/2 cup unsweetened cocoa powder
• 1 teaspoon baking soda
• 3/4 teaspoon salt
• 1/2 cup whole milk
• 1/2 cup sour cream (4 ounces)
• 8 ounces (2 sticks) unsalted butter, plus more for pan
• 1 1/2 cups sugar
• 4 large eggs
• 1 teaspoon pure vanilla extract
• 1/2 cup chopped walnuts (optional)
• 3 ounces bittersweet chocolate, chopped
• 1/2 cup heavy cream
• 2 tablespoons unsalted butter
• 2 tablespoons Cognac or rum (optional)
• Tangerines, for serving