How to Make It
Preheat the oven to 400°. Butter and flour sixteen 3 1/2-inch-long barquettes or 30 mini muffin pan cups.
In a food processor, grind the almonds to a fine powder. In a bowl, mix the almond powder and sugar. Whisk in the eggs until incorporated, then whisk in the melted butter, followed by the flour. Spoon the batter into the prepared barquette molds or mini muffin cups and decorate with the pistachios. Bake the cakes until golden brown, about 12 minutes for barquettes and 16 minutes for mini muffins. Let cool slightly, then run a knife around each cake and transfer them to a rack to cool.
If you want to skip grinding the almonds, use 1 cup of almond flour.