In a large bowl, cream butter and sugar. Beat in eggs and extract. Combine the flour, baking powder, baking soda and salt; gradually add to the creamed mixture and mix well. Cover and refrigerate for 1 hour or until easy to handle., On a lightly floured surface, roll out dough to 1/4-in. thickness; cut with a floured 2-in. round cookie cutter. Place half of the circles 2 in. apart on ungreased baking sheets. Crumble 1/2 teaspoon almond paste over each; top with remaining circles. Pinch edges to seal., Cut a small slit in top of each cookie. Brush with egg white. Press an almond in each slit. Bake at 350° for 10-12 minutes or until lightly browned. Remove to wire racks to cool.