In a food processor, process walnuts into meal. Add flour, baking powder, and sugar. Add egg whites, honey, and vanilla. Cook butter to brown stage. Pour hot butter over the egg whites-nut mixture. Give a few pulses until well combined. Fill up greased and almond coated pizza pan, or tart pan. The thickness of financier should not go over 2 inches/2.5cm.
Pre-heat oven to 350ºF/180ºC. Bake walnut financier for 25/30 minutes. Enjoy!