Mississippi Mud Pie

1 (8-inch) prepared chocolate crumb crust
1 cup powdered sugar
1 cup (6 ounces) semisweet chocolate chips
1/4 cup butter or margarine, cut up
1/4 cup heavy whipping cream
2 tablespoons light corn syrup
1 teaspoon vanilla extract
3/4 cup chopped nuts, divided (optional)
2 pints coffee ice cream, softened slightly, divided
Lightly sweetened whipped cream (optional)

Heat sugar, chocolate chips, butter, cream and corn syrup in small saucepanover low heat, stirring constantly, until butter is melted and mixture issmooth. Remove from heat. Stir in vanilla extract. Cool until slightly warm.Drizzle 1/3 cup chocolate sauce in bottom of crust; sprinkle with 1/4 cupnuts. Layer with 1 pint ice cream; freeze for 1 hour.Repeat with 1/3 cup sauce, 1/4 cup nuts and ice cream. Drizzle withremaining sauce; top with remaining nuts. Freeze for 2 hours or until firm.Serve with a dollop of whipped cream, if desired.Makes 8 servings.