Melt butter and chocolate together over low heat or in the microwave, cool slightly Preheat oven to 350 degrees and Grease cookie sheets.
In a medium bowl, mix eggs, vanilla and sugar with an electric mixer until smooth. Stir in melted chocolate mixture. Sift together the flour, baking powder, and salt . Stir dry ingredients into the egg mixture by hand until well blended. Refrigerate for at least 1 hour.
Shape rounded teaspoonfuls into balls and roll in confectioners' sugar. Place cookies 2 inches apart on prepared cookie sheets. Bake for 8 to 10 minutes or until soft to touch.