Step 1: Make the Crust
Preheat oven to 325°F (163°C). Grease a 9-inch springform pan.
Mix graham cracker crumbs, melted butter, and sugar until combined.
Press into the bottom of the pan and slightly up the sides.
Bake for 10 minutes, then set aside to cool.
Step 2: Prepare the Cheesecake Filling
In a large bowl, beat cream cheese and sugar until smooth.
Add eggs one at a time, mixing after each addition.
Mix in sour cream, flour, lemon juice, lemon zest, and vanilla extract until combined.
Pour the filling over the crust and smooth the top.
Step 3: Bake the Cheesecake
Wrap the bottom of the springform pan in aluminum foil and place it in a water bath (a roasting pan filled with 1 inch of hot water).
Bake for 55-60 minutes, or until the center is slightly jiggly.
Turn off the oven, crack the door, and let the cheesecake sit for 30 minutes.
Remove from the oven and refrigerate for at least 4 hours (or overnight).
Step 4: Make the Lemon Curd
In a small saucepan over medium heat, whisk together lemon juice, zest, sugar, and egg yolks.
Stir constantly for 5-7 minutes, until thickened.
Remove from heat and stir in butter until melted.
Let cool completely, then spread over the chilled cheesecake.
Step 5: Prepare the Meringue
In a clean bowl, beat egg whites and cream of tartar on high speed until soft peaks form.
Gradually add sugar, 1 tablespoon at a time, until stiff peaks form.
Mix in vanilla extract.
Step 6: Assemble And Toast
Spread or pipe the meringue over the lemon curd layer.
Use a kitchen torch to toast the meringue until golden. Alternatively, broil in the oven for 1-2 minutes, watching closely.
Step 7: Serve And Enjoy!
Slice and serve chilled.