Almond-Orange Financier

Preheat the oven to 450°F. Brush the inside of a 4 × 13 1/2-inch tart pan that has a nonremovable bottom with melted butter; transfer to the freezer.

Using a food processor, pulse the almonds until finely ground. In a large bowl, combine the ground almonds, confectioners’ sugar, flour, salt, and orange zest. Add the egg whites, and whisk to combine. Slowly stir in the butter.

Remove the tart pan from the freezer. Pour the batter into the pan; place on a baking sheet. Bake until the dough just begins to rise, about 10 minutes. Reduce the oven heat to 400°F, and continue baking 7 to 8 minutes more, until the financier begins to brown. Turn off the oven, and let the cake stand in the oven until firm, about 10 minutes. Transfer the pan to a wire rack to cool completely.