For the chocolate cupcakes, beat the sugar with the room-warm butter until fluffy. Add the eggs. Mix the flour with the baking powder and stir in.
Add a few tablespoons of milk and a pinch of salt and stir well for a few minutes. Bake in a preheated oven for about 15 minutes at 180 °C convection oven.
Let cool well, otherwise the topping will melt. Cut the butter into small pieces. Mix well with the powdered sugar and cream cheese. If desired, color with a little food coloring.
Use a piping bag with a star nozzle to pipe the topping onto the cupcakes and decorate with colorful sprinkles and, if desired, with homemade flags.