In medium bowl, mix crushed cookies and 1/2 cup melted butter. Press mixture firmly in bottom of ungreased 8x8-inch pan.

Spoon softened ice cream evenly over cookie crust. Freeze about 2 hours or until firm.

In small saucepan, melt 1/4 cup butter and 2 squares (2 oz) chocolate over low heat, stirring constantly. Stir in sugar; gradually stir in evaporated milk.

Heat to boiling over medium-high heat, stirring constantly. Cook and stir 5 minutes or until slightly thickened; stir in vanilla. Cool completely, about 2 hours.

Pour 1 cup of the chocolate sauce evenly over ice cream. Freeze at least 6 hours but no longer than 2 weeks. Cover and refrigerate remaining sauce.

Optional to reheat the remaining sauce and drizzle over each serving.

To serve, cut into 4 rows by 3 rows. Top with sauce and remaining whipped topping; sprinkle with crushed candies.