In a saucepan over medium heat, melt the butter. Continue cooking, swirling the pan occasionally, until the butter turns a golden-brown color and smells nutty. This usually takes about 5-7 minutes. Be careful not to burn it! Once browned, remove from heat and let it cool slightly.

In a medium bowl, whisk together the almond flour, powdered sugar, all-purpose flour, baking powder, and salt. This ensures everything is evenly distributed.

Add the slightly cooled browned butter to the dry ingredients. Stir until just combined. The mixture will be thick.

In a separate bowl, lightly whisk the egg whites until they are slightly frothy. Add the egg whites and almond extract to the batter. Mix until everything is well combined and the batter is smooth.

Cover the bowl with plastic wrap and refrigerate the batter for at least 30 minutes. This step is crucial as it allows the batter to firm up and the flavors to meld together.

Preheat your oven to 375°F (190°C). Grease a financier mold or muffin tin very well with butter. You can also dust it with flour to prevent sticking.

Spoon the batter into the prepared molds, filling each about three-quarters full.

Bake for 15-18 minutes, or until the edges are golden brown and a toothpick inserted into the center comes out clean.

Let the Financiers cool in the pan for a few minutes before transferring them to a wire rack to cool completely.