PreparationMake meringue layers: Preheat oven to 300°F. In a large baking pan toast almonds in one layer in middle of oven 15 to 20 minutes, or until fragrant and golden, and cool completely. Line 2 baking sheets with parchment paper. Using a 9-inch springform pan as a guide, trace a circle on each piece of parchment and turn paper over. (Circle will show through.) In a food processor pulse together almonds, 3/4 cup sugar, and cornstarch until almonds are ground fine. In the large bowl of a standing electric mixer beat egg whites with cream of tartar and salt until they hold soft peaks. Add almond extract and remaining 2 tablespoons sugar, 1 tablespoon at a time, beating until meringue holds stiff, glossy peaks. Fold in almond mixture gently but thoroughly and divide meringue evenly between parchment circles, spreading it to fill in circles. Bake meringue layers in upper and lower thirds of oven 1 hour, or until golden. (Layers will not be completely firm.) Turn oven off. Switch positions of sheets and let layers stand in oven 2 hours, or until dry. Carefully peel off parchment. Meringue layers may be made 1 day ahead and kept, wrapped well in plastic wrap, in a cool, dry place (not the refrigerator). With a small sharp knife trim edges of meringue layers just enough to fit inside springform pan. Put 1 layer in pan. Scoop 1 pint ice cream and 1 cup praline butter into bowl of standing mixer and with paddle attachment distribute praline butter evenly throughout ice cream to marbleize it. (Do not over-mix or let ice cream melt.) Spread marbled ice cream over meringue layer in pan and top with remaining meringue layer, gently pressing it into ice cream. Freeze cake, covered with plastic wrap, 30 minutes. Beat remaining 1 cup praline butter into remaining 1 pint ice cream in same manner as above and spread over meringue layer. Freeze cake, covered with plastic wrap, at least 30 minutes, or until ice cream is firm. In a chilled bowl beat heavy cream with sugar until it just holds stiff peaks and spread over ice cream. Freeze ice-cream cake 30 to 45 minutes, or until whipped cream is firm. Cover cake with plastic wrap and foil and freeze at least 4 hours or overnight. Immediately before serving the cake, wrap a warm dampened kitchen towel around side of pan and run a thin knife around cake to loosen it. Remove side of pan and transfer cake to a serving plate. Cut cake into wedges with a knife dipped repeatedly in hot water and serve garnished with pieces of almond praline if desired.
PreparationMake meringue layers: Preheat oven to 300°F. In a large baking pan toast almonds in one layer in middle of oven 15 to 20 minutes, or until fragrant and golden, and cool completely. Line 2 baking sheets with parchment paper. Using a 9-inch springform pan as a guide, trace a circle on each piece of parchment and turn paper over. (Circle will show through.) In a food processor pulse together almonds, 3/4 cup sugar, and cornstarch until almonds are ground fine. In the large bowl of a standing electric mixer beat egg whites with cream of tartar and salt until they hold soft peaks. Add almond extract and remaining 2 tablespoons sugar, 1 tablespoon at a time, beating until meringue holds stiff, glossy peaks. Fold in almond mixture gently but thoroughly and divide meringue evenly between parchment circles, spreading it to fill in circles. Bake meringue layers in upper and lower thirds of oven 1 hour, or until golden. (Layers will not be completely firm.) Turn oven off. Switch positions of sheets and let layers stand in oven 2 hours, or until dry. Carefully peel off parchment. Meringue layers may be made 1 day ahead and kept, wrapped well in plastic wrap, in a cool, dry place (not the refrigerator). With a small sharp knife trim edges of meringue layers just enough to fit inside springform pan. Put 1 layer in pan. Scoop 1 pint ice cream and 1 cup praline butter into bowl of standing mixer and with paddle attachment distribute praline butter evenly throughout ice cream to marbleize it. (Do not over-mix or let ice cream melt.) Spread marbled ice cream over meringue layer in pan and top with remaining meringue layer, gently pressing it into ice cream. Freeze cake, covered with plastic wrap, 30 minutes. Beat remaining 1 cup praline butter into remaining 1 pint ice cream in same manner as above and spread over meringue layer. Freeze cake, covered with plastic wrap, at least 30 minutes, or until ice cream is firm. In a chilled bowl beat heavy cream with sugar until it just holds stiff peaks and spread over ice cream. Freeze ice-cream cake 30 to 45 minutes, or until whipped cream is firm. Cover cake with plastic wrap and foil and freeze at least 4 hours or overnight. Immediately before serving the cake, wrap a warm dampened kitchen towel around side of pan and run a thin knife around cake to loosen it. Remove side of pan and transfer cake to a serving plate. Cut cake into wedges with a knife dipped repeatedly in hot water and serve garnished with pieces of almond praline if desired.