Melt shortening in a small saucepan over low heat; remove from heat, and set aside to cool slightly.
Combine flour, baking powder, and salt in a small mixing bowl; stir well, and set aside.
Combine melted shortening and sugar in a large mixing bowl; beat until well blended. Add eggs, peanut butter, and vanilla, beating well. Gradually add reserved flour mixture to peanut butter mixture, stirring well after each addition. Fold in chocolate morsels and peanuts.
Spread mixture evenly in a well-greased 13- x 9- x 2-inch baking pan. Bake at 350° for 35 minutes. Cool completely in pan; cut into 3- x 1 1/2-inch bars.