All ingredients must be at room temp. Blend cream cheese, sour cream and butter.
Add cornstarch, sugar, vanilla and lemon juice. Beat until well-blended.
Beat in one egg at a time, continuing to beat until mixture is light and smooth.
Pour into well greased 9” springform pan. (Place the pan on a large square of aluminum foil, and bring the foil up around the sides tightly to prevent water seeping in during baking.) Place the filled pan in a larger pan containing warm water to come halfway up the sides of the springform pan.
Bake at 375° for one hour until the top is golden and center is fairly firm. Turn oven off and let cake cool in it with door open for a least one hour.
Allow to stand at room temp to cool completely about 2 hours. Then cover and refrigerate several hours. About 20 minutes before serving, take out of refrigerator, remove ring and place on cake platter.
Preheat the oven to 350 degrees F. Lightly grease a 13 by 9 by-2- inch baking pan.
In the bowl of an electric mixer, combine the cake mix, egg, and butter and mix well. Pat into the bottom of prepared pan and set aside.
For the filling: Still using an electric mixer, beat the cream cheese until smooth. Beat in the eggs and vanilla.
Dump in confectioners' sugar and beat well.
Reduce the speed and slowly pour in butter. Mix well.
Fold in toffee bits.
Pour filling onto cake mixture and spread evenly. Bake for 40 to 50 minutes. Don't be afraid to make a judgment call on the cooking time, because oven temperatures can vary. You want the center to be a little gooey, so don't bake it past that point!
Remove from oven and allow to cool completely. Cut into squares. Just remember that these wonderful cakes are very, very rich, and a little will go a long way.