Cut the sponge cake into 3 equal pieces to fit into the bottom of a 9 by 5 by 3-inch loaf pan. Line the loaf pan with plastic wrap, leaving an overhang over the sides. Lay 1 piece of cake flat in the pan. Sprinkle about 2 1/2 tablespoons of liqueur evenly over the cake. Spread one-third of the softened ice cream over the cake, smoothing the top with a rubber spatula and top with another cake layer. Repeat the process, working carefully to create 3 layers of cake soaked with liqueur and ice cream on top. Wrap with the plastic wrap and place in the freezer to firm up the ice cream, 1 to 2 hours.
To make the caramel sauce, in a medium, heavy saucepan, combine the sugar and water, and bring to a boil. Lower the heat to medium-low and cook, stirring occasionally, until the sugar is dissolved. Continue cooking until amber in color, about 7 minutes, swirling the pan occasionally. Remove from the heat and slowly add 3/4 cup of the cream. Return to low heat and stir until the sauce is smooth, about 1 minute. Remove from the heat and add 2 teaspoons of the almond liqueur. Let rest until cool but still liquid, about 40 minutes.
In a bowl, whip the remaining 2 cups of cream until stiff peaks start to form. Add the powdered sugar and whip into stiff peaks. Add the remaining 2 teaspoons of liqueur and whip to incorporate.
Place the frozen toffee bars in a plastic bag and smash into pieces with a mallet or rolling pin.
Remove the layered ice cream cake from the freezer. Lift from the loaf pan and remove the plastic wrap. Place the cake on a platter. Spread the whipped cream over the top and sides of the cake. Sprinkle the top and sides with the broken Heath bar pieces and drizzle the cake with the caramel sauce.
To serve, slice into 1-inch thick servings with a knife dipped in hot water.
Yield: 8 servings