Preheat the oven to 180 ° C.

Mix the butter with the sugar and the eggs. Beat by hand or in a food processor until the mixture turns white.

Stir in the milk.

Add the flour and baking powder.

Mix until obtaining a smooth paste.

Stir in the blueberries.

Pour into pre-buttered muffin tins or with boxes.

Bake for 25 to 30 minutes. Take out and let cool.

Whisk the mascarpone with the icing sugar.

Decorate the muffins with the mascarpone either with a spoon, or better using a piping bag.