1. Preheat the oven to 180°C (350°F). Line a mini muffin tin* with mini paper liners*. For a better result, you might want to leave every second mold empty so the cupcakes can rise undisturbed. Set it aside.

2. Add sugar, butter, and vanilla extract to a large bowl and mix until very light and fluffy. Add the eggs one after another and mix well after each addition. Combine flour, baking powder, baking soda, and salt. Add the dry ingredients alternating with the buttermilk to the large bowl and mix until just combined. If you want to add sprinkles to the dough, you can add them now and fold them in (optional). Fill the mini cupcake liners max. 3/4 full and bake the first batch of cupcakes for about 11-12 minutes or until a toothpick inserted into the cupcakes comes out clean. Take out of the oven, remove from the muffin tin, and let cool down completely on a wire rack. Repeat with the remaining dough until everything has been used.

3. For the buttercream, add the butter to the bowl of a kitchen machine and mix on high for about 4-5 minutes until the butter is very light and fluffy. Gradually add the confectioners’ sugar and mix in. Continue mixing for about 4-5 minutes, then add the heavy cream and vanilla extract and mix a few minutes longer to get a nice and fluffy buttercream.

4. Transfer the buttercream to a piping bag with a star tip and pipe a small swirl onto each cupcake and sprinkle with rainbow sprinkles and confetti. Place in the fridge until ready to serve.