How to Make It
Preheat the oven to 400°. Butter and flour 36 mini muffin cups. In a saucepan, cook the 7 ounces of butter over moderate heat, shaking the pan, until the milk solids begin to brown, about 5 minutes. Scrape the butter and browned solids into a bowl and let cool. Whisk in the brown sugar, egg whites, granulated sugar and almond extract.
In another bowl, whisk the pistachios with the 1 cup of all-purpose flour, the cake flour and the salt. Fold the dry ingredients into the brown butter mixture until combined.
Spoon the batter into the muffin cups and bake for about 15 minutes, until risen but still slightly soft in the center. Let cool slightly, then invert onto a rack to cool. Serve the financiers with crème fraîche and berries.