For first layer, in a medium mixing bowl combine 1/2 cup melted butter or margarine and granulated sugar. Add chocolate wafer crumbs; mix well. Press mixture into the bottom of an ungreased 8x8x2-inch baking pan; chill about 20 minutes or until firm.

For second layer, in a large mixing bowl beat cream cheese and 1/4 cup butter or margarine with an electric mixer on medium speed until mixture is fluffy. Add the 1/3 cup powdered sugar; beat until combined. Stir in chopped pecans and the 1 teaspoon vanilla. Spread over crumb layer. Chill about 30 minutes or until set.

For third layer, beat peanut butter and half of the 1 cup powdered sugar until combined. Add 1 tablespoon of the milk and the 1/2 teaspoon vanilla. Beat until smooth. Gradually add remaining powdered sugar, beating until smooth. Add additional milk, if necessary, to make of spreading consistency. Spread over cream cheese layer.

Drizzle with Chocolate Drizzle. Arrange pecan halves on drizzle. Cover and chill at least 2 hours before serving. Makes 24 bars.

Heat 1/3 cup milk chocolate pieces and 1/2 teaspoon shortening in a small saucepan over low heat until melted, stirring occasionally.

Up to 3 days ahead, prepare bars. Place in an airtight container and store in the refrigerator.