From "Jamie's America"
1/2 stick (1/4 cup) unsalted butter, at room temperature
3/4 cup superfine sugar
1 large egg, preferably free-range or organic
1 tsp. good-quality vanilla extract
Optional: 3 tbsp. natural red food colouring
2 heaping tbsp. unsweetened cocoa powder
1 1/4 cups all-purpose flour
1/2 cup buttermilk
1/2 tsp. baking soda
1 1/2 tsp. white wine vinegar
3/4 x 8-oz. cream cheese (I used light)
1/2 stick (1/4 cup) unsalted butter, at room temp.
1 cup + confectioners' sugar
1/2 tsp. vanilla extract
(zest and juice of 1 lemon)-- just as good without it
Preheat the oven to 350 F and line a 12-hole muffin pan with paper liners
Using an electric mixer, or by hand, cream your butter and sugar together until light and fluffy. Gently beat in the egg, a pinch of salt, the vanilla extract, and red food colouring. in a separate bowl, whisk together the cocoa and flour and fold half of it into your butter mix, followed by half the buttermilk. Repeat with the remaining flour and buttermilk until you have a gorgeous smooth texture.
In a small bowl, mix your baking soda and white wine vinegar together so it fizzes up, and stir this into your cake mix.
Divide the mixture between your paper liners and bake in the oven for 20-25 minutes. To check they're cooked through, insert a skewer into the center of a cake -- if it comes out clean, they're perfect, if not, just pop them back into the oven for another couple of minutes. Let them cool for 5 minutes in the pan, then transfer to a wire rack to cool completely while you make your frosting.
Put all your frosting ingredients into a bowl and mix together until smooth and creamy. (Jamie says spoon the frosting onto the cupcakes, I used a piping bag to make them prettier...)