1. Preheat the oven to 350°F (180°C). Line a muffin tin with paper liners and set aside.

2. In a large bowl mix the butter and sugar until very light and fluffy. Add the egg and mix until well combined. Add the egg whites one after another and mix until well combined. Add the vanilla extract and stir in. Mix the flour with baking powder, baking soda, and salt and add alternating with the buttermilk in 2-3 batches to the bowl – mix each time until just combined. “Sir Mix-a-Lot” I know ;P Divide the batter between the paper liners and bake for about 20-24 minutes or until a toothpick inserted in the center of a cupcake comes out clean. Take out of the oven and let cool down completely on a wire rack.

3. For the buttercream clean some strawberries and then puree them – you need about 1 cup (240ml) of strawberry puree. Add to a small saucepan and slowly heat up while stirring constantly. Let simmer over medium heat until the puree has thickened and you are left with 3-4 tablespoons of a thicker strawberry puree. This takes about 10-15 minutes. Let cool down completely.

4. Dice the strawberries for the filling, add them to a bowl together with sugar and vanilla liquor and let them marinate for several minutes.

5. As soon as the strawberry puree has cooled down you can continue with the buttercream. Add the butter to a large bowl and mix until light and fluffy. Add about half of the confectioners’ sugar and mix until well combined. Add the strawberry puree and vanilla extract and mix in. Add more confectioners’ sugar and mix on high to get a nice and fluffy strawberry buttercream.

6. Core the cupcakes with a knife or cupcake corer*. Place diced strawberries (including any liquids from the marinating process) in those holes. Fill the buttercream into a piping bag with a star tip and decorate the cupcakes with it. Make sure you cover the diced strawberries completely. To finish the cupcakes you can place a small strawberry on top of each cupcake (optional).