Preheat oven to 350 degrees F. Lightly grease the bottom of a 9-inch springform pan. Wrap a double layer of foil around the bottom and side of pan to form a watertight seal; set aside. For crust: In a medium bowl, stir together crushed gingersnaps and the 2 tablespoons granulated sugar. Stir in melted butter. Press mixture onto the bottom of the foil-wrapped pan. Bake about 14 minutes or until crust starts to brown. Cool on a wire rack.
In a very large bowl, beat cream cheese with an electric mixer on medium speed until fluffy. Add brown sugar and flour; beat until smooth. Add eggs and egg yolks one at a time, beating after each addition just until combined. Beat in vanilla. Pour over crust, spreading evenly. Place the foil-wrapped springform pan in a roasting pan. Pour enough hot water into roasting pan to reach halfway up side of springform pan.
Bake about 1-1/4 hours or until a 2-inch area around the outside edge appears set and the center appears nearly set when gently shaken. Remove springform pan from water. Cool in pan on wire rack for 15 minutes. Using a small sharp knife, loosen edge of cheesecake from side of pan; cool completely (about 1-3/4 hours). Remove foil. Cover and chill overnight.
Prepare Caramel Topping. Remove side of springform pan; transfer cheesecake to a serving plate.
Spoon topping onto cheesecake, spreading to cover top. Garnish with chopped English toffee. Cover loosely and chill for 2 to 6 hours.
In a large saucepan, combine granulated sugar, water, and lemon juice. Cook over medium heat, stirring to dissolve sugar. Bring to boiling; reduce heat. Without stirring, boil gently, uncovered, for 9 to 12 minutes or until mixture turns a deep amber color, occasionally swirling pan and brushing down the side with a wet pastry brush. Add 1 cup whipping cream (mixture will bubble); reduce heat to medium-low. Simmer, uncovered, for 12 to 15 minutes or until reduced to 1 1/3 cups, stirring occasionally. Chill about 30 minutes or until thickened but still pourable.