Step 1

Preheat oven to 350°F.

Step 2

Invert the bottom of a 9-inch springform pan so the cheesecake can slide off onto a serving platter once chilled. Line with a round of parchment paper, if desired.

Step 3

In a food processor, process the graham crackers to fine, even crumbs, about 30-seconds. Add the sugar and salt, and pulse 2 or 3 times to combine. Add the warm melted butter in a slow, steady stream while pulsing. Process until the mixture is evenly moistened and resembles wet sand.

Step 4

Transfer the mixture to the prepared 9-inch springform pan. Using the bottom of a dry measuring cup, press the crumb mixture into the bottom and 1-inch up the sides of the pan. Don't press too hard. Slightly firm is good. Bake until set and fragrant, about 8 to 10 minutes. Remove to a wire rack to cool for at least 30 minutes before filling.

Step 5

Once cooled, wrap the bottom and sides of the pan in a double layer of heavy-duty foil. Set the springform pan in a roasting pan.

Step 6

Reduce the oven temperature to 325°F.

Step 7

In the bowl of a clean food processor, combine ⅓ cup of sugar with the lemon zest. Pulse until the sugar is pale yellow and the zest is broken down. Transfer the lemon sugar to a 2-cup measuring cup with a spout. Whisk in the remaining 1 cup of sugar and the flour. Set aside.

Step 8

In the bowl of a stand mixer fitted with the paddle attachment, beat the cream cheese until smooth and creamy. Scrape down the sides and bottom of the bowl. With the mixer running on medium-low, slowly add the lemon sugar mixture. Beat until the mixture is smooth, scraping down the sides and bottom of the bowl as needed.

Step 9

With the speed set on medium, add the eggs, one at a time, beating just until the yolk disappears before adding the next. Scrape down the sides and bottom of the bowl, beat again to blend. Be careful not to over beat.

Step 10

Add the lemon juice, vanilla and sour cream. Beat on low until combined. Scrape down the sides and bottom of the bowl, and beat again for another 5 seconds or until well blended.

Step 11

Pour the batter into the prepared pan. Fill the outer roasting pan with enough hot tap water to come halfway up the sides of the springform pan.

Step 12

Bake at 325°F until the center jiggles slightly, the sides start to puff and the surface appears dry, about 90 to 100 minutes.

Step 13

Turn off the oven and prop the oven door open using a pot holder or wooden spoon. Allow the cheesecake to cool in the hot water bath for 1 hour. Transfer the cheesecake to a wire rack and remove the foil. Slide a small thin knife around the inside edge of the pan to loosen the sides of the cheesecake. Leave the cheesecake in the springform pan and cool to room temperature, about 2 hours.

Step 14

When the cheesecake is cool, spread the lemon curd on top of the cheesecake leaving a 1-inch border around the edge. Cover tightly with plastic wrap and refrigerate overnight, or up to 24 hours.

Step 15

Remove the sides of the springform pan and carefully slide the cheesecake onto a serving platter. Pipe or dollop whipped cream around the outer edges of the cheesecake and garnish with fresh lemon slices, if desired. Slice into wedges and serve.

Step 16

In a cold medium mixing bowl using an electric mixer, beat the whipping cream on medium speed until soft peaks form. Add the powdered sugar and vanilla and beat on high until firm peaks form. Dollop or pipe the whipped cream on top of the cheesecake in a decorative pattern.