Financiers (French Mini Almond Cakes)

Name: Financiers (French Mini Almond Cakes)
Prep time: 15 min
Cook time: 22 min
Total time: 37 min
Yield: 24
Ingredients: 5.3 ounces unsalted butter (about 10 tablespoons; 150g); 3.5 ounces toasted blanched sliced almonds (about 1 cup; 100g); 2.1 ounces all-purpose flour (about 1/2 cup; 60g); 6.3 ounces (1 1/2 cups; 180g) powdered sugar, sifted; 1/4 teaspoon Diamond Crystal kosher salt; for table salt, use half as much by volume; 4 large egg whites (120g), lightly beaten; Raw sliced almonds, for decorating