Line a 8 x 8 inch baking dish with plastic wrap, letting the wrap extend by a few inches on two sides.  Arrange 6 ice cream sandwiches, with sides touching, in 2 rows of 3 each.  Spread with 1 cup thawed Cool Whip, then sprinkle with 1/3 cup toffee bits.  Top with 6 more ice cream sandwiches.  Freeze until firm.

Holding plastic wrap extending above sides of pan, lift cake and invert onto a serving platter.  Remove plastic wrap, spread top of cake with 1 cup Cool Whip and sprinkle with 1/3 cup toffee bits.  To serve, slice crosswise.  Drizzle with bottle chocolate sauce, if desired.