Blanch the eggs with the sugar. This means mixing the eggs and sugar with a whisk until the mixture turns pale yellow (easier with a food processor or an electric mixer).
Add the flour, baking powder and melted butter to this mixture.
Mix and refrigerate for one hour.
Preheat the oven to 220 ° C.
Butter the mussels and sprinkle a little flour on the mussels. Turn them over to remove the excess flour.
Fill the molds three-quarters full. Add a teaspoon of milk jam. Cover with a little dough.
Bake for about 8 minutes.
Take out the madeleines.
Unmould the madeleines and repeat the operation until you have no more dough.