Prepare Pan: Grease a 9-inch springform pan and line the bottom with parchment paper.
Mix: Combine 2 cups graham cracker crumbs, 1/3 cup granulated sugar, and 1/2 cup melted unsalted butter in a bowl.
Press: Press the mixture onto the bottom and up the sides of the prepared pan.
Bake: Bake the crust for 10 minutes or until lightly golden. Then, remove it from the oven and let it cool while preparing the filling.
Cheesecake Filling:
Beat: In a large bowl, beat 24 ounces of cream cheese until smooth and creamy.
Add Sugar: Add 1 cup granulated sugar and beat until well combined.
Add Eggs: Add 3 large eggs, one at a time, beating well after each addition.
Mix: Stir in 1/4 cup fresh lemon juice, 2 teaspoons lemon zest, and 1/2 cup sour cream until well combined.
Pour: Pour the cheesecake batter into the cooled crust and smooth the top with a spatula.
Bake: Bake the cheesecake for 45-50 minutes or until set around the edges but still slightly jiggly in the center.
Lemon Curd:
Whisk: In a medium saucepan, whisk together 3 large eggs and 3/4 cup granulated sugar until well combined.
Cook: Add 1/2 cup fresh lemon juice, 6 tablespoons unsalted butter, and 1 tablespoon lemon zest to the saucepan. Cook over medium heat, whisking constantly, until the mixture thickens and coats the back of a spoon (about 10-15 minutes). Remove from heat and let it cool to room temperature.
Meringue:
Beat: In a clean mixing bowl, beat 4 large egg whites and 1/4 teaspoon cream of tartar on medium-high speed until soft peaks form.
Gradually Add Sugar: Gradually add 1/2 cup granulated sugar, 1 tablespoon at a time, while beating on high speed, until stiff peaks form.
Assembly:
Spread: Once the cheesecake is done baking, spread the cooled lemon curd evenly over the top of the cheesecake.
Meringue: Spread the meringue over the lemon curd, covering the edges of the cheesecake to prevent any cracks.
Bake Again: Bake the cheesecake for an additional 10-15 minutes or until the meringue is golden brown.
Cool and Serve: Remove the cheesecake from the oven and let it cool to room temperature before chilling in the refrigerator for at least 2 hours before serving.