Method

• 1.
  Whiz flour and icing sugar in a food processor until smooth. Add butter and a pinch of fine salt and whiz until very fine crumbs form. Add yolks and iced water and whiz, in bursts, until mixture comes together into a ball. Turn out onto a piece of plastic wrap and lightly bring together using your hands to form a flat disc. Enclose tightly and chill for at least 2 hours.
• 2.
  Grease a 22cm (base), 23cm (top), 2.5cm-deep tart pan with removable base. Roll pastry out on a lightly floured surface to a 5mm-thick round, then quickly transfer to prepared pan, pressing in gently while easing into side of pan (dough will become softer the more it is handled). There will be an 8mm overhang. Chill for at least 2 hours or until firm.
• 3.
  Preheat oven to 200°C/180°C fan-forced. Place a baking tray in the oven to preheat.
• 4.
  Whiz flour and icing sugar in a food processor until smooth. Add butter and a pinch of fine salt and whiz until very fine crumbs form. Add yolks and iced water and whiz, in bursts, until mixture comes together into a ball. Turn out onto a piece of plastic wrap and lightly bring together using your hands to form a flat disc. Enclose tightly and chill for at least 2 hours.
• 5.
  For the filling, whisk yolks, eggs and sugar in a large heatproof bowl until well combined, then set aside. Place lemon zest, lemon juice and finger lime skin in a medium saucepan over medium-high heat and bring to the boil. Whisk 2 tbs hot lemon mixture into the egg mixture until well combined, then strain remaining lemon mixture into eggs, whisking constantly, until smooth and well combined. Return mixture to same pan and reduce heat to medium-low. Cook, whisking constantly, for 5-7 minutes until very thick and smooth. Remove pan from heat and add butter, one piece at a time, whisking until melted and well combined before adding the next piece. Continue whisking until all butter is added and mixture is very glossy and smooth, with a texture like pouring custard.
• 6.
  Pour lemon and finger lime filling into cooled pastry shell and level surface. Stand for 10 minutes at room temperature, then chill for at least 2 hours or until set firm.
• 7.
  Place cream and mascarpone in the bowl of a stand mixer fitted with the whisk attachment. Whisk on medium-high speed for 1-2 minutes until soft peaks form. Spoon cream over tart, then sprinkle with extra zest and reserved finger lime pearls. Serve.