1½ cup powdered sugar for rolling and to sift over finished cookies
Preheat oven to 350 degrees. In a mixing bowl, sift flour with baking powder and salt and set aside.
In top of a double-boiler over simmering water, melt butter and chocolate. Stir in sugar and mix until sugar is fully dissolved. Set aside to cool slightly.
Stir eggs into chocolate one at a time. Add vanilla bean seeds. Add dry ingredients in thirds, mixing well after each addition. Chill dough for at least 30 minutes.
Form 1 tablespoon of dough into a ball and roll in powdered sugar, then place on a parchment-lined cookie sheet and slightly flatten. Repeat with remaining dough. Bake for 10 to 12 minutes. Sift powdered sugar over cookies before serving.