Melt the butter over medium-low heat until it turns brown.
Sift the cake flour and almond flour together.
Add sugar to the egg whites and mix with a whisk.
Add the sifted flours to the egg whites and mix well.
Add the melted butter and combine thoroughly.
Let the batter rest in the refrigerator for 30 minutes.
Fill the financier molds with the batter.
Bake in a preheated oven at 180°C for 15 minutes.