Lemon-Lime Cheesecake

Ingredients

• 3 tablespoons granulated sugar
• 1/4 cup (2 oz) unsalted butter, at room temperature
• 1 1/2 teaspoons grated lemon zest
• 1 egg yolk
• 1 cup (5 oz) all-purpose flour
• 1/4 teaspoon baking powder
• pinch of salt
• 1 1/4 lb (625g) cream cheese, at room temperature
• 3/4 cup (6 oz) granulated sugar
• 3/4 cup (6 fl oz) sour cream
• 1 tablespoon grated lemon zest
• 1 tablespoon grated lime zest
• 2 tablespoons fresh lemon juice
• 2 tablespoons fresh lime juice
• 4 eggs
• 2 oranges, blood oranges or tangerines
• 1 lemon
• 1 lime
• 1 grapefruit
• 3 1/2 cups (1 1/2 lb) superfine sugar
• 3/4 cup (6 fl oz) water