Financiers (French Mini Almond Cakes)

Brown the Butter - In a 2-quart stainless steel saucepan or saucier, melt butter over medium-low heat. Increase heat to medium and simmer, stirring with a heat-resistant spatula while butter hisses and pops. Continue cooking and stirring until foaming subsides, scraping up brown bits that form on bottom, and butter is golden yellow and milk solids are chestnut brown in color, about 5 minutes. Transfer to a small heatproof bowl and set aside.

Make the Batter - In a blender or food processor, combine toasted almonds and flour and pulse until almonds are completely broken down into fine, sandy crumbs, about 30 seconds. Transfer flour-almond mixture to a large bowl, add sugar and salt, and whisk until thoroughly combined, about 30 seconds. Add egg whites and whisk until smooth and no dry flour remains, about 1 minute (the consistency should be similar to pancake batter). Add half of the brown butter and whisk until fully incorporated, about 30 seconds. Repeat with remaining butter. Cover bowl with plastic wrap and refrigerate for at least 3 hours and up to 1 day.

Bake the Financiers - Adjust oven rack to middle position and preheat oven to 375°F (190°C). Grease a 24-cup nonstick mini muffin pan. Using a 1-tablespoon cookie scoop or measuring spoon, scoop 1 tablespoon of dough into each cup. Sprinkle raw sliced almonds in an even layer over the top of each. Bake until financiers are puffed and domed on top and light golden brown in the center with deeper golden brown edges, about 12 minutes.

Cool and Serve - Transfer pan to a wire rack and let cool for 10 minutes. Using a butter knife or small, thin offset spatula, remove financiers from pan. Serve slightly warm or at room temperature.