Heat oven to 350 degrees F (325 degrees F for dark or nonstick pan). Spray bottom only of 13x9-inch pan with Crisco® Original No-Stick Cooking Spray.
In medium bowl, stir 1/2 cup melted butter, 1 1/2 cups of the cracker crumbs and 3/4 cup of the toffee bits. Press mixture evenly in bottom of pan. Refrigerate about 15 minutes or until firm.
Meanwhile, let cookie dough stand at room temperature 10 minutes to soften. In 2-quart saucepan, heat chocolate chips, milk and 1 tablespoon butter over medium heat, stirring frequently, until chips are melted and mixture is smooth. Remove from heat; stir in vanilla. Spread mixture over cracker crust.
In medium bowl, break up cookie dough. Mix in remaining 1/2 cup cracker crumbs with wooden spoon until well blended. Crumble mixture evenly over chocolate layer. Sprinkle with remaining 3/4 cup toffee bits.
Bake 25 to 35 minutes or until golden brown. Cool completely, about 2 hours. For a firmer bar, refrigerate 30 minutes longer. For bars, cut into 8 rows by 4 rows.