Melt the butter and let it cool.
In a bowl, mix the egg whites and sugar well.
Sift in the flour, almond flour, and baking powder, then mix thoroughly.
Add the melted butter to make the batter.
Pour the batter into financier molds and bake in a 170°C oven for 15 minutes.
After cooling, melt the dark chocolate using a double boiler.
Dip one side of the financier into the chocolate to coat and let it set.