- Crust and Filling:
- Softened butter or solid vegetable shortening for greasing the pan
- 1 package (18.25 ounces) plain white cake mix
- 4 tablespoons (½ stick) butter, melted
- 4 large eggs
- 2 packages (8 ounces each) cream cheese, at room temperature
- 1 can (14 ounces) sweetened condensed milk
- ½ cup sour cream
- 2 tablespoons fresh lemon juice
- 2 teaspoons pure vanilla extract
- 1 cup sour cream
- ¼ cup sugar
1. Place a rack in the center of the oven and preheat the oven to 325°F. Lightly grease a 13 by 9 inch baking pan with softened butter or vegetable shortening. Set the pan aside.
2. Measure out ½ cup of the cake mix and set aside for the filling.
3. Place the remaining cake mix, the melted butter, and 1 egg in a large mixing bowl. Blend with an electric mixer on low speed for 2 minutes. Stop the machine and scrape down the sides of the bowl with a rubber spatula. The batter should come together in a ball. With your fingertips, pat the batter evenly over the bottom and 1 inch up the sides of the prepared pan, smoothing it out with your fingers until the top is smooth. Set the pan aside.
4. For the filling, place the cream cheese and the sweetened condensed milk in the same mixing bowl that was used to make the crust, and with the same beaters (no need to clean either) blend with an electric mixer on low speed until just combined, 30 seconds. Stop the machine and add the reserved cake mix, the remaining 3 eggs, the sour cream, lemon juice, and vanilla and beat on medium speed for 1 minute. Stop the machine and scrape the sides of the bowl with a rubber spatula. Pour the filling onto the crust and spread with the rubber spatula so that the filling covers the entire surface and reaches the sides of the pan. Place the pan in the oven.
5. Bake the cheesecake until it looks shiny and the center no longer jiggles when you shake the pan. 35 to 40 minutes. Remove the pan from the oven while you prepare the topping. Leave the oven on.
6. For the topping, place the sour cream and sugar in a small mixing bowl and stir with a spoon until well combined. Pour the topping over the cheesecake, and return the pan to the oven.
7. Bake until the topping sets, 7 to 10 minutes. Remove the pan from the oven and place it on a wire rack to cool, 30 minutes. Lightly cover the pan with plastic wrap and place the pan in the refrigerator to chill for at least 1 hour, but preferably 24 hours for the flavors to meld. Cut into squares and serve.
* Store this cake, covered in plastic wrap or aluminum foil, in the refrigerator for up to 1 week. Or freeze it, wrapped in foil, for up to 2 months. Thaw the cake overnight in the refrigerator before serving.