CRUST:

1 1/2 c. graham cracker crumbs
6 tbsp. (3/4 stick) unsalted butter, melted
1/4 c. firmly packed dark brown sugar

FILLING:

2 lbs. cream cheese, room temperature
1 1/2 c. sugar
5 lg. eggs, room temperature
2 1/2 tsp. vanilla extract
2 tsp. fresh lemon juice

TOPPING:

1 1/4 c. sugar
1/3 c. water
1 c. whipping cream
1/2 c. (1 stick) unsalted butter, cut into small pieces, room temperature
1 tsp. vanilla extract
3/4 c. whipping cream
2 tbsp. sugar
3 (1.4 oz.) toffee candy bars (Skor) broken up

For Crust: Preheat oven to 350 degrees. Lightly butter side of 9 inch diameter springform pan with 2 3/4 inch high sides. Combine crumbs, butter and brown sugar in small bowl. Press crumbs over bottom and 1 inch up sides of pan. Refrigerate crust.

For Filling: Using electric mixer, beat cream cheese in large bowl until fluffy. Add sugar and beat until smooth. Beat in eggs one at a time. Mix in vanilla extract and fresh lemon juice.

Pour filling into prepared crust. Bake until cake rises about 1/2 inch over rim and center moves only slightly when pan is shaken, about 1 hour and 15 minutes. Cool on rack. Cake will fall as it cools, sinking in center. Cover and refrigerate until well chilled, at least 6 hours.

For Topping: Heat sugar and water in heavy medium saucepan over low heat, stir until sugar dissolves. Increase heat and boil within stirring until mixture is rich caramel color, occasionally swirling and washings down sides of pan with brush dipped into cold water for about 8 minutes. Reduce heat very low. Add cream (mixture will bubble up) and stir until smooth. Mix in butter. Cool and slightly mix in vanilla.

Using a knife, cut around the side of pan to loosen cake. Pour 2/3 cup of caramel sauce into center of cake. Cover remaining caramel sauce and let stand at room temperature. Chill cake until caramel topping has almost set about 2 hours.

Whip 3/4 cup cream with 2 tablespoons sugar in medium until firm peaks form. Spoon cream into pastry bag fitted with star tip. Pipe cream decoratively around edge of cake. Arrange toffee pieces in whipped cream border. Put in refrigerate until serving. Cut cake into wedges. Serve, passing remaining caramel sauce separately.