Preheat your oven to 325°F (160°C).

In a mixing bowl, combine the graham cracker crumbs with melted butter and sugar until resembling damp sand. Press into a 9-inch springform pan and bake for about 10 minutes or until golden. Let cool.

Using an electric mixer, beat the cream cheese and sugar until smooth. Add eggs one at a time, incorporate sour cream, lemon zest, lemon juice, and vanilla extract. Pour over the cooled crust.

Place the filled springform pan into a larger baking dish filled with water. Bake for 50-60 minutes until the center is set but slightly jiggly. Cool in the oven for about an hour, then refrigerate for at least 4 hours.

While the cheesecake cools, prepare the lemon curd by whisking egg yolks, sugar, lemon juice, and zest in a saucepan over low heat for 8-10 minutes until thickened. Stir in butter until melted. Pour over the cheesecake and refrigerate until set.

Beat egg whites with cream of tartar until soft peaks form. Gradually add sugar until stiff peaks form, then fold in vanilla extract.

Preheat your oven to 350°F (175°C). Spread meringue over the lemon curd, creating peaks. Bake for 10-15 minutes until golden brown.

After baking, allow to cool briefly before refrigerating for another hour. Slice and serve chilled, optionally garnished with fresh lemon slices or berries.