Preheat the oven at 350F (180C).

Sift together buckwheat flour, cake flour, and baking powder.

Separate eggs in two bowls. Add half of sugar to yolks and beat with whisk for a couple of minutes. Beat egg whites, add sugar, and whip until forming hard peaks, a meringue. Fold yolk mixture into meringue, then add flour mixture and fold in. Mix until all the flour is well mixed, but do not overmix.

Put the batter in a piping bag with a 1/3" (8-9mm) round piping tip. Place a silicon mat on a baking sheet. For each cookie, pipe on the mat five 1/3" dots barely touching each other forming a flower shape.

Bake in the oven about 12-15 minutes or until the cookies brown.