Ingredients
4 tablespoons unsalted butter, room temperature, plus more for tin
1/3 cup sugar, plus more for tin
8 ounces bittersweet chocolate, coarsely chopped
1/3 cup all-purpose flour
1 tablespoon instant espresso powder
1/4 teaspoon coarse salt
3 large eggs
1 teaspoon pure vanilla extract
Ganache glaze (optional)
Preparation
Preheat oven to 400 degrees. Brush 6 cups of a standard muffin tin with butter and dust with sugar; tap out excess. Melt chocolate in a heatproof bowl set over (not in) a pan of simmering water, stirring until smooth. Let cool.
In a bowl, whisk together flour, espresso powder, and salt. With a mixer on medium-high speed, beat butter with sugar until light and fluffy. Add eggs, one at a time, mixing until completely incorporated. Add flour mixture; beat until combined. Beat in vanilla and chocolate.
Spoon batter into prepared cups. Bake until cakes no longer jiggle when tin is shaken, 8 to 10 minutes. Let cool on a wire rack 10 minutes before turning out cakes. Spread ganache over tops and serve.
