An absolutely perfect ice cream cake recipe drizzled with a chocolate sauce that is to die for.
To make the cake:
In a bowl with a fork stir together the crumbs and the butter until the mixture is combined well, pat the mixture into the bottom and 1 inch up the side of a lightly oiled 8-inch springform pan, 2 1/2 inches deep, and freeze the crust for 30 minutes, or until it is firm.
Spread the ice cream evenly on the crust and return the pan to the freezer for 30 minutes, or until the ice cream is firm.
In a bowl with an electric mixer beat the cream with the vanilla until it holds stiff peaks, fold in the chocolate wafers thoroughly, and spread the mixture over the ice cream.
Smooth the top of the cake, sprinkle with crushed amaretti cookies and freeze the cake for 30 to 45 minutes, or until the top is firm.
Freeze the cake, covered with plastic wrap, for at least 4 hours or overnight.
Just before serving, transfer the cake to a serving plate.
Cut the cake into wedges with a knife dipped in hot water and serve it with the chocolate sauce.
To make the sauce:
In a small heavy saucepan combine the cream and brown sugar, bring the mixture to a boil over moderately high heat, whisking occasionally, and boil it, whisking, until the brown sugar is dissolved.
Remove the pan from the heat and add the chocolates, whisking until they are melted.
Whisk in the butter, whisking until sauce is smooth, and let cool slightly.
The chocolate sauce may be made 1 week in advance and kept covered and chilled.
Reheat the chocolate sauce over very low heat, stirring occasionally, until it is warm.