1. Prepare the Crust

Preheat your oven to 325°F (160°C). Grease a 9-inch springform pan and line the bottom with parchment paper. In a mixing bowl, combine the graham cracker crumbs, 1/3 cup granulated sugar, and melted butter until the mixture resembles wet sand. Press the mixture firmly into the bottom of the prepared pan. Bake for 10 minutes and set aside to cool.

2. Make the Cheesecake Filling

In a large mixing bowl, beat the room-temperature cream cheese until it’s smooth and free of lumps. Gradually add the 1 cup of sugar, continuing to beat until fully incorporated. Mix in the 1/4 cup of fresh lemon juice and 2 teaspoons of lemon zest. Add the 1/2 cup sour cream and mix until combined. Beat in the eggs one at a time, ensuring each is fully mixed before adding the next. Pour the cheesecake filling over the cooled crust.

Bake in the preheated oven for 50-60 minutes, or until the edges are set and the center is slightly jiggly. Turn off the oven and let the cheesecake cool inside with the oven door slightly ajar for 1 hour to prevent cracking. Remove and cool completely at room temperature before refrigerating for at least 4 hours.

3. Prepare the Lemon Curd

While the cheesecake chills, make the lemon curd. In a medium saucepan, whisk together the 6 tablespoons of butter, 3/4 cup of sugar, 3 large eggs, 1/2 cup of lemon juice, and 1 tablespoon of zest over medium heat. Stir constantly to prevent curdling. After 7-10 minutes, the mixture should thicken to a pudding-like consistency. Strain through a sieve to remove any lumps and let cool. Refrigerate until ready to use.

4. Whip Up the Meringue

Place the 4 large egg whites in a clean bowl and beat until frothy. Add the 1/4 teaspoon of cream of tartar and continue beating. Gradually add the 1/2 cup of sugar while beating until stiff peaks form. The meringue should hold its shape and appear glossy.

5. Assemble and Toast

Spread the chilled lemon curd evenly over the top of the cheesecake. Spoon or pipe the meringue on top, ensuring it reaches the edges to seal in the lemon curd. For a dramatic finish, use a kitchen torch to toast the meringue until golden brown, or place the cheesecake under a broiler for 1-2 minutes, watching closely to prevent burning.