1 ounce good-quality semisweet chocolate, finely chopped
½ cup hot water
1 cup granulated sugar
¾ cup plus 1 Tbs unbleached all-purpose flour
½ cup unsweetened cocoa powder
Heaping ½ tsp baking soda
¼ tsp baking powder
Scant ½ tsp salt
1 large egg
¼ cup canola oil
½ cup buttermilk
¼ tsp pure vanilla extract
2 cups powdered sugar
1 Tbs unsweetened cocoa powder
1/3 cup malted milk powder, such as Carnation
9 Tbs (1 stick plus 1 Tbs) unsalted butter, at room temperature
2 Tbs boiling water
Preheat the oven to 300 degrees. Line 12 cups of a muffin tin with paper liners.
Place the chocolate in a medium bowl with the hot water. Let stand, stirring occasionally, until the chocolate is melted and the mixture is smooth and opaque. In another medium bowl, combine the sugar, flour, cocoa powder, baking soda, baking powder, and salt, and whisk to combine well.
Divide the batter evenly among the 12 prepared muffin cups. Bake for 20-25 minutes, or until a toothpick inserted in the center of a cupcake comes out clean. Cool the cupcakes for 15 minutes in the pan; then very carefully transfer them to a rack to cool completely. Take heed when removing them from the pans- they do crumble easily.
When the cupcakes are cool, make the frosting. Combine the powdered sugar, cocoa, and malted milk powder with an electric mixer; combine well. Add the butter, and stir well. Scrap down the sides of the bowl with a rubber spatula. Add the water slowly and stir to incorporate until it's all nice and smooth. Frost the cupcakes and serve.
Cover and refrigerate for storage.