Preheat the oven to 355°F (180°C). Grease the cavities of a mini muffin pan with the softened butter using a pastry brush.

Cut butter into small pieces and melt it in the microwave at 20-second intervals. Let it cool to room temperature. Alternatively, place butter pieces in a small saucepan and melt over low heat, stirring.

In a medium bowl, combine almond flour, cocoa powder, icing (powdered) sugar, and all-purpose flour and set aside.

In a separate bowl, beat egg whites with an electric mixer for about 15-20 seconds.

Add egg whites to the flour mixture and mix with a rubber spatula. Add the melted butter and gently mix until just combined.

Transfer the financier batter to a piping bag with the cut tip, and pipe it into molds filling up to two-thirds.

Bake for 6 minutes. Open the oven and carefully insert a cherry with a stem into each financier. Continue baking for the other 6 to 8 minutes until a cake tester or a toothpick comes out clean.

Cool in the tins for 5 minutes, then flip the mini muffin pan over to unmold the cakes and let cool completely on a wire rack.