How to make
Melt the butter and with about 1 tablespoon of it, grease the forms for the madeleines. Leave the forms in the refrigerator for 15 minutes to tighten the butter.
Melt the chocolate separately in a water bath. Once melted, take away from the heat, but leave it in a hot water bath.
Grind the hazelnuts and 1/3 of the sugar. Transfer the mixture to a small bowl and stir in the flour.
Separately, beat the egg whites with 1 drop of freshly squeezed lemon juice with the mixer on high speed. This takes about 30 seconds - until you get a white, fluffy foam. Gradually add the remaining sugar and beat quickly until they form their characteristic hard, white tips.
If the beating process continues too long, this can prevent the madeleines from retaining their characteristic shape during baking.
Gradually add flour to the egg whites and mix. Add the melted butter, which needs to be at room temperature. Finally mix in the warm chocolate and vanilla.
Allow the mixture to set in the fridge for 10 minutes. Remove the floured madeleine forms from the refrigerator.
Distribute the mixture up to 2/3 of the height of the forms. Bake for 15 minutes in a preheated 370°F (190 °C) oven.
Leave the finished cookies to cool before removing them from the forms. They are perfect for afternoon coffee or tea.
