~from Savoring Time in the Kitchen
Makes 11 cupcakes (yes, that's not a typo). Use less batter in each cupcake liner if you want 12 cupcakes. I like mine a little higher.
4 tablespoons unsalted butter
1/4 cup vegetable oil
1/2 cup water
1 cup cake flour (for homemade cake flour, measure 1 cup flour into a bowl, remove 1 tablespoon flour and then add 1 tablespoon corn starch – blend with a fork or whisk)
1 cup granulated sugar
1/4 cup plus 2 tablespoons unsweetened cocoa powder (not Dutch process), I used Ghirardelli
3/4 teaspoon baking soda
1/8 teaspoon salt
1 large egg
1/4 cup buttermilk (you can make your own buttermilk by stirring in 1/2 teaspoon of vinegar to 1/4 cup regular milk and allow it to sit for 10 minutes, stir again before using)
1 teaspoon pure vanilla extract
Preheat the oven to 350°. Line a 12-cup muffin tin with paper or foil cupcake liners.
In a small saucepan, melt the butter with the vegetable oil and water over low heat. As soon as the butter is melted, remove from heat.
In a large bowl, sift the flour, sugar, cocoa powder, baking soda and salt together. Stir until blended together. Add the melted butter mixture and beat with a handheld mixer at low speed until smooth. Beat in the egg and then the buttermilk and vanilla. Beat until smooth for about one minute, scraping the bottom and sides of the bowl. Pour the batter into the lined muffin tins, filling them about three-fourths full.
Bake the cupcakes in the center of the oven for about 25 minutes, until springy and a toothpick inserted in the center comes out clean. Let the cupcakes cool slightly, then transfer them to a rack to cool completely. Unfrosted cupcakes can be wrapped in plastic and stored at room temperature for up to 2 days or frozen for up to 1 month.
Chocolate Ganache Frosting
4 ounces bittersweet chocolate, finely chopped. I used Ghirardelli 60% Bittersweet baking bar
1/2 cup heavy cream
3 tablespoons butter
1 tablespoon light corn syrup (I only use 1 teaspoon)
1/8 teaspoon salt
Put the chopped chocolate into a heatproof bowl, such as a 4-cup Pyrex measuring bowl. In a small saucepan, heat the cream, butter, corn syrup and salt until hot but not boiling. Pour the hot mixture over the chocolate and leave alone for 1-2 minutes. Then start stirinbg , and then stir until smooth and dark with no remaining traces of cream (start stirring in circles in the center and then work outward).
Let the frosting cool, stirring occasionally, until thick enough for dipping and glazing the cupcakes, about 30 minutes. For a frosting firm enough to spread, place in refrigerator and stir every 5 minutes until it’s firm enough to use as frosting. If it becomes too stiff just bring it back to room temperature. The frosting can be refrigerated in an airtight container for up to 3 days. Return to room temperature before using.
Adapted from Food and Wine