Preheat your oven to 325°F (160°C).

For the crust, mix together the graham cracker crumbs, sugar, and melted butter in a bowl. Press this mixture firmly into the bottom of a 9-inch springform pan. Bake for about 10 minutes, then set aside to cool.

For the cheesecake filling, beat the cream cheese and sugar in a large mixing bowl until smooth and creamy. Add in the eggs one at a time, mixing well after each addition. Stir in the sour cream, lemon juice, and all the citrus zest.

Pour the cheesecake filling onto your cooled crust and smooth the top with a spatula. Bake for 50-60 minutes or until the center is set, but still jiggles slightly.

For the meringue, beat the egg whites in a separate bowl until soft peaks form, then add the cream of tartar. Gradually add in the sugar, maintaining peaks until glossy and stiff.

Spread the meringue on top of your cheesecake and create swirls and peaks with a spatula.

Return the cheesecake to the oven and bake for an additional 10-15 minutes, until the meringue is golden brown.

Allow the cheesecake to cool at room temperature for an hour before refrigerating for at least 3 hours.