Preheat the oven to 325ºF.

To make the shortbread, soften the unsalted butter in a bowl. Add the sugar, semolina flour and all-purpose flour and mix together until a smooth dough begins to form. Wrap the dough in clingfilm and chill in the fridge for 15 minutes.

On a lightly floured surface, roll out the chilled dough. Evenly line the 9" tart tin with the crust and generously prick the dough with a fork.

Bake for 25-30 minutes, until the crust is a light golden brown. Briefly cool before adding 6 Tbsp (120g) of lemon curd on the cooled shortbread crust.

In a stand mixer with the whip attachment*, whip the heavy whipping cream, powdered sugar, and vanilla together on medium speed for 2 minutes.

Add the remaining 1/2 C (160g) of the lemon curd to the whipped cream and continue mixing on medium speed for 2 minutes.

Add the whipped lemon curd to the shortbread crust and smooth the edges. Chill in the fridge for 1-2 hours, until the filling has set.