• Preheat the oven to 400°F. You are going to start the muffins in a very hot oven and then turn it down to 325° F. after the first 5 minutes. Line 6 jumbo size muffin cups with paper liners.
• Also, bring all ingredients to room temperature including the sour cream. You can let everything sit out for an hour or do it quickly. To bring eggs to room temperature, dunk them in warm water for about 30 seconds. To bring sour cream to room temperature, you can use whatever method you like. I heat it on a very low setting of the microwave for 20 or so seconds just so it's not ice cold. The butter should be extremely soft, especially if you are beating the batter together by hand.

Easy Ganache Topping

• Make the ganache first. In a little custard cup or ramekin, heat the cream in the microwave just until it starts to boil. Add the chopped chocolate or chips and let stand for 5 minutes. Stir until smooth, then stir in 1 tablespoon of confectioners' sugar. Set aside to cool and thicken somewhat

Muffin Batter

• In a medium size bowl, whisk together the flour, cocoa powder, baking powder, salt, espresso powder and cinnamon (if using). Whisk until very evenly blended, then set aside.
• In a mixing bowl, using an electric mixer or by hand, beat the softened butter with the sugar until blended. Don't try to whip too much air into it, just beat until creamy. Beat in the egg, the yolk and the extracts.
• Add the flour mixture to the egg mixture and stir until about halfway blended, then add the sour cream and stir until batter is smooth and silky.
• Stir in the chocolate chips.
• Put the batter in the muffin tins, dividing evenly. Now spoon a teaspoon or so of the ganache on top of batter.
• Set your timer for 5 minutes. Bake the muffins at 400 degrees F. for 5 minutes, then reduce the heat to 325 and bake for another 20 minutes. Let cool for about 10 minutes, then carefully remove from the muffin tin.