1For the Cheesecake: Pulse the first 3 ingredients in a food processor 3 or 4 times or just until blended. Add the butter, and pulse 5 or 6 times or until crumbly.
2Whisk together the egg yolks and 1 tablespoon ice-cold water in a small bowl; add to the butter mixture, and process until dough forms a ball and pulls away from the sides of the bowl, adding up to 1 tablespoon remaining ice-cold water one teaspoon at a time, if necessary. Shape the dough into a disk; wrap in plastic wrap. Chill for 4 - 24 hours.
3Roll the dough into a 14 inch circle on a lightly floured surface. Fit the dough into a lightly greased 0 inch dark springform pan, gently pressing on the bottom and up the sides of the pan; trim and discard the excess dough. Chill 30 minutes.
4Meanwhile, preheat the oven to 325 degrees. Beat the cream cheese at medium speed with an electric mixer for 3 minutes or until smooth. Gradually add 1 cup granulated sugar, beating until blended. Add eggs, one at a time, beating just until the yellow disappears after each addition. Beat in the vanilla.
5Pour two-thirds of the cheesecake batter (about 4 cups) into the prepared crust; dollop 1 cup lemon curd over the batter in the pan, and gently swirl with a knife. Spoon the remaining batter into the pan.
6Bake at 325 degrees for 1 hour to 1 hour and 30 minutes or just until the center is set. Turn the oven off. Let the cheesecake stand in the oven with the door closed, 15 minutes. Remove the cheesecake from the oven, and gently run a knife around the outer edge of the cheesecake to loosen from the sides of the pan. (Do not remove sides of pan.) Cool completely in the pan on a wire rack (about 1 hour). Cover and chill 8 to 24 hours.
7Remove the sides of the pan, and transfer the cheesecake to a serving platter. Spoon the remaining 1 cup lemon curd over the cheesecake, and if desired, top with candied lemon slices.
8For the candied lemon slices: Stir together 1 cup sugar, 2 tablespoons fresh lemon juice, and 3/4 cup water in a large skillet over medium heat until the sugar is dissolved. Add the lemon slices, and simmer gently, keeping the slices in a single layer and turning occasionally, 14 to 16 minutes or until slightly translucent and the rinds are softened. Remove from the heat. Place the slices in a single layer on a wax paper-lined jellyroll pan, using tongs. Cool completely (about 1 hour) Cover and chill 2 hours to 2 days. Reserve the syrup for another use.