Grind almonds finely and mix with 150 grams (approximately 1/3 pound) of sugar and almond extract.
Beat egg whites until stiff and sprinkle in remaining sugar.
Add the almond mixture spoonful-by-spoonful to the beaten egg whites and stir until smooth.
Grease the baking sheet and sprinkle with flour.
Fill a pastry bag with a smooth nozzle with the mixture and squeeze out walnut-sized blobs onto the baking sheets, and let sit for about 2 hours. Bake at 150°C (approximately 300°F) for about 45 minutes.