Doubly Lemon Cupcakes

Directions

1. 1
   Preheat oven to 180°C (about 355°F) and line a cupcake tin with 12 cases.
2. 2
   For the cupcakes, sieve the flour and baking powder into a medium-sized bowl and leave to one side. Place the butter, sugar and lemon zest in the bowl of your stand mixer or a large bowl. Beat until light and fluffy. Add in the lemon juice, egg and egg white and mix again until smooth.
3. 3
   Add in the flour and mix until just incorporated. Add in the sour cream. Beat until well incorporated and nice and smooth. It should be a lovely smooth, glossy consistency. Place the batter in the cupcake cases. You'll pretty much fill them to the top; this is fine, this batter doesn't rise too much, but still ends up being lovely and light because of the sour cream.
4. 4
   Place in the oven and bake for 20-25 minutes, until firm to touch and a skewer comes out clean. They won't be very browned, we're looking for very lightly coloured muffins. This is because of the sour cream too, in case you're not familiar with adding it to cupcakes. Take the cakes out of the tin almost immediately and then leave to cool completely on a wire rack.
5. 5
   When the cakes are cooled completely, make the frosting. Place the sugar, butter, cream cheese, lemon juice and zest in a large bowl. Beat until light and fluffy. Fill a piping bag halfway, then pipe a swirl onto each cupcake. This recipe for frosting makes enough to pipe 12 cupcakes. If you are just spooning the frosting on, you may want to halve the recipe. I finished mine off with some sprinkles.
6. 6
   Because of the frosting, these really need to be kept in the fridge especially as summer seems to have arrived in the UK finally! Cream cheese frosting + heat = a big slidey mess. Will keep for up to 3 days.