Previously posted here by Betsy/TRL in November 1997

PEANUT BUTTER BARS
Source: the LA Times California Cookbook
Makes about 5 dozen

18 oz Jar peanut butter, at room temperature
3/4 cup Margarine or softened butter
1 lb Powdered sugar
1 lb Box Graham Crackers Coarsley crushed
12 oz Semi-sweet chocolate pieces

Using an electric beater, cream together the peanut butter and margarine until very soft and smooth. Beat in the powdered sugar until smooth, then beat in HALF the crumbs. Beat until well blended and moist. Mix in the remaining crumbs BY HAND. Spread the mixture in a 13 x 9 inch baking pan, patting evenly. Melt chocolate in top of double boiler over hot water or in microwave and pour over cracker mixture, Mark off desired size squares or bars and refrigerate overnight.