Line an 8 inch square pan as follows: Turn the pan over, cover with a 12 inch square of aluminum foil shiny side down, fold down the sides and corners to shape the foil, remove the foil, turn the pan over again and place the foil into the pan, pressing it carefully to fit smooth.
In the large bowl of an electric mixture (or any large bowl with a wooden spatula), mix the butter with the cookie crumbs, sugar and peanut butter.
Turn into the lined pan.
With the bottom of a teaspoon, smooth the mixture to make an even layer.
Let stand at room temperature.
Break up the chocolate and melt in the microwave or on top of a double boiler.
Stir until completely melted and smooth.
Pour the chocolate on to the peanut butter layer.
With the bottom of a teaspoon smooth all the chocolate over the bottom layer, touching the sides of the foil.
Refrigerate for an hour (or longer), until firm.
Lift the candy from the pan by lifting the aluminum foil.
Place the candy, still on the foil, on a cutting board.
Fold down the sides of the foil and let stand.
If you cut this into squares while cold it will crumble.
Let it stand for about an hour, then cut into 32 small squares.