Ingredients:
2 cups confectioners' sugar (if lumpy, sift before measuring)
2 cups graham cracker crumbs
3/4 cup peanut butter
3/4 cup unsalted butter, cut into thin pats
1/2 cup miniature semisweet chocolate chips

Topping:
8 ounces semisweet chocolate
1 tablespoon solid vegetable shortening

For Bars:
Line an 8-inch square pan (at least 1-1/2 inches deep) with two sheets of regular aluminum foil, one on top of the other, smoothing out as many creases as possible. The foil should overhang the pan on at least two sides. Fold any overhang back against the outer edges of the pan.

In large bowl, combine confectioners' sugar and graham cracker crumbs. With hand-held electric mixer on lowest speed (or use a large spoon), mix well (if you use a spoon, press out any lumps with the back of it). Add peanut butter, but do not stir.

In small saucepan over very low heat, melt butter, stirring often. Do not let the butter get hot! Keep it on the heat until it's almost melted, then remove from heat and stir until completely melted. Pour into graham cracker mixture. With mixer at low speed (or with large spoon), blend thoroughly until all ingredients are combined. Scrape bottom and sides of bowl with rubber spatula. When ingredients are well-blended, stir in chips until evenly distributed (use a spoon to stir in the chips).

Turn mixture into lined pan. Using the back of a spoon, spread as evenly as possible. Set aside at room temperature while Topping is prepared.

For Topping:
In small heatproof bowl, combine chopped chocolate and vegetable shortening. Place over simmering water on low heat (water should not touch bottom of bowl). Stir often until almost melted. Remove from heat and hot water; dry bowl bottom and sides. Stir until completely melted and smooth. Pour onto peanut butter mixture in pan. With back of a teaspoon, spread as evenly as possible over top of peanut butter mixture. Place in refrigerator; chill at least two hours, covering tightly when cold.

To cut:
These must stand at room temperature for about an hour before you cut them; if you try to cut them when they're cold, they'll fall apart. Remove the uncut bars, still in foil, from the pan. Place on a cutting board; gently peel back foil from sides. Allow to stand for about one hour. You'll need a large, sharp, heavy, straight-edged knife for cutting. Using the tip of the knife, heavily score the chocolate topping several times where you want to make the cuts. Most cut between 36 to 48 bars - depending on need and/or preference. Once you have scored the bars, go back and cut.

Store the bars airtight in the refrigerator, or freeze them.