PREHEAT OVEN TO 350F. Melt the semisweet chocolate and the butter over low heat or in the microwave. Stir until smooth. Sift together the flour, baking powder and salt. Beat eggs, sugar and vanilla at high speed until well combined. Slowly beat in the cooled chocolate, then the dry ingredients until just blended but smooth. Stir in the chocolate morsels and the nuts. Drop by heaping teaspoonfuls 1 inch apart on cookie sheets lined with parchment paper or aluminum foil. Bake 10-to-12 minutes. Do not over bake. Cool on a rack. May be made ahead or frozen.