• Adjust oven rack to middle position and preheat oven to 325ºF. Line a baking sheet with foil and set aside.

Prepare the crust

• In a food processor, add the graham crackers and process cookies to fine, even crumbs, about 30 seconds. Skip this step if you are using store-bought graham cracker crumbs.
  1 ½ cups graham crackers
• Add the sugar and salt and pulse 2 or 3 times to incorporate.
  3 tablespoons granulated sugar, ¼ teaspoon salt
• Add the warm melted butter in a slow, steady stream while pulsing. Continue to pulse until the mixture is evenly moistened and resembles wet sand.
  6 tablespoons unsalted butter
• Transfer the crust mixture to a 9-inch springform pan. Using the flat bottom of a dry measuring cup, press firmly and evenly into the bottom of the pan, and up the sides, if desired.

  Place the pan with crust on top of a foil-lined baking sheet and set aside.

Prepare the cheesecake filling

• In the cleaned bowl of your food processor, add ¼ cup sugar and lemon zest in the food processor until sugar is yellow and zest is broken down, about 15 seconds, scraping down bowl if necessary.

  Transfer lemon sugar to a small bowl and stir in the remaining 1 cup sugar until evenly combined.
  1 ¼ cups granulated sugar, 1 tablespoon lemon zest
• In the bowl of a stand mixer fitted with paddle attachment, beat the softened cream cheese on low to break up any chunks of cream cheese and smooth out, about 30-60 seconds.
  3 8-ounce packages cream cheese
• Add the sugar mixture and increase the mixer speed to medium. Continue to beat until the mixture is creamy and smooth, about 3 minutes. Scrape the sides and bottom of the bowl with a rubber spatula as needed.
• Add the lemon juice, vanilla, and salt and mix until just incorporated.
  ¼ cup lemon juice, 2 teaspoons vanilla extract, ¼ teaspoon salt
• Add in sour cream and beat just until incorporated. Scrape the bottom and sides of the bowl and stir with a rubber spatula to ensure all is evenly mixed.

  Then pour the filling mixture on top of the crust.
  ½ cup full-fat sour cream

Bake

• Place the cheesecake in the preheated oven in the center of the middle rack. Bake until the center jiggles slightly and the surface is no longer shiny, about 65-80 minutes.
• Turn off the oven but keep the cheesecake in the oven for 1 hour. Open the oven door slightly and prop it open with a wooden spoon, if needed. This allows the cheesecake to cool, but slowly, allowing the center to set.
• After about 1 hour, remove from the oven and run a knife gently around the outside of the cheesecake (between the cheesecake and the pan) to loosen the crust from the inside of the springform pan. Do not remove the ring of the springform pan just yet.
• Allow the cheesecake to cool to room temperature, about 2 hours.

Top the cheesecake

• When the cheesecake is cool, pour the lemon curd onto the cheesecake in the springform pan. Use a spatula to spread the curd evenly over the top of the cheesecake.
  1 - 1 ¼ cups store-bought lemon curd
• Cover the cheesecake tightly with foil or plastic wrap and refrigerate for at least 4 hours or up to 24 hours.
• To serve, remove the sides of the springform pan and cut the cake into wedges.