Preheat your oven to 325°F (163°C). In a mixing bowl, combine graham cracker crumbs, granulated sugar, and melted butter. Stir until sand-like. Press into the bottom of a 9-inch springform pan. Bake for 10 minutes until set and golden. Let cool.

In a large bowl, beat cream cheese until smooth for about 3 minutes. Gradually add granulated sugar and mix until fluffy. Add sour cream, blending well. Incorporate eggs one at a time, then add vanilla extract, lemon zest, and lemon juice.

In a small bowl, whisk together heavy cream, cornstarch, and salt until smooth. Gradually pour into the cheesecake filling, stirring until combined. Pour into the cooled crust, smoothing the top.

Bake the cheesecake for 55-60 minutes until the center is set but slightly jiggly. Turn off the oven and leave the cake inside for about an hour. Cool to room temperature, then refrigerate overnight.

To make meringue, beat egg whites with cream of tartar until soft peaks form, about 3-5 minutes. Gradually add sugar while beating until stiff peaks form. Mix in warm lemon juice and vanilla extract.

Spread meringue over the cheesecake, creating peaks and swirls. Preheat oven to 350°F (177°C) and bake for 8-10 minutes until lightly golden and crispy. Watch closely to avoid burning.

Cool for 15 minutes before removing the sides of the springform pan. Chill for an hour in the refrigerator before slicing and serving.