Press a sheet of aluminum foil into a 9-inch by 13-inch pan with a 2-inch overhang on each long side. This will act like a cradle that will help you remove the frozen cake for easier slicing if you wish. If you prefer, you can skip this step and cut it in the pan.

Arrange one box of the ice cream sandwiches in a single layer on the bottom of the pan, cutting if necessary.

Warm up the hot fudge sauce if necessary to make it spreadable then use a silicone, rubber, or offset spatula to spread it evenly over the ice cream sandwiches. Put that in the freezer while you whip the cream to firm peaks. Remove the pan from the freezer and spread the whipped cream evenly over the hot fudge.

Drizzle about 1/2 of a cup of the butterscotch caramel (warming slightly if necessary to make it pourable) over the whipped cream then open two packages of the broken Twix bars and scatter it over the top.

Arrange the second box of ice cream sandwiches over the top and gently press them into the whipped cream. Spread the remaining butterscotch caramel over the top and toss the other two broken Twix bars over the top of the caramel. Put the whole pan into the freezer until very firm, at least 2 hours. If you are going to wait longer than 2 hours to slice it, cover it tightly with plastic wrap after it is firm to prevent freezer burn.

You can either use the foil to remove the cake from the pan for easier slicing, or you can slice it in the pan.

Optional: Drizzle each serving with more hot fudge sauce before serving.