Melt shortening and chocolate together over hot water; cool.
Sift flour with baking powder and salt. Beat eggs until light; add sugar, then chocolate mixture and blend. Stir in sifted flour, vanilla and nuts. Mix well.
Pour batter into greased 8x8x2-inch pan.
Bake in moderate (350º) oven for 30 to 35 minutes.
Cool on rack and cut into squares
Recipe submitted by ~Donna~ V on 7/14/98