Start by browning the butter. Cool to room temperature then chill in the fridge until firm.
Preheat an oven to 160°c & grease & line a 9”x9” square baking tin.
Next, place the caster sugar & lemon zest into the bowl of a stand mixer & massage the zest into the sugar.
Add in the chilled brown butter & using the paddle attachment, beat until light & fluffy, around 3-4 minutes.
Next, weigh the flours, semolina & salt into a bowl & whisk together.
Add the lemon curd & flours into the butter & sugar mixture & mix until just combined, around 30 second.
Finally, using a spatula or wooden spoon, stir in the white chocolate until combined evenly.
Transfer the dough to the prepared baking tin & use a palette knife to spread the shortbread into an even layer. Next, use a dough scraper or knife to lightly score the shortbread into 12 even rectangles.
Sprinkle the granulated sugar over the top then bake for 20-25 minutes or until firm & a light golden brown round the edges.
Leave to cool in the tin for 5 minutes then whilst still in the tin, portion the shortbread into the 12 pieces that were scored before baking.
Leave to cool fully in the tin before serving.