1. Preheat oven to 170C.

2. Line a lamington tin (approximately 30cm x 20cm x 3cm) with baking paper, making sure it hangs generously over the sides to make lifting the slice out nice and easy.

3. For the shortbread base, add all the ingredients plus a pinch of salt to a bowl and stir to combine. Press down into the prepared tin and pop in the oven for 30 minutes or until lightly golden, then set aside.

4. While the base is baking, make the filling. Whisk together the eggs, yolks, sugar, salt, lemon zest and juice and butter in a medium saucepan until smooth. Place the saucepan over low heat and whisk, fairly continuously, until the mixture thickens to a fudge sauce-like consistency. It should hold its shape but also pour.

5. Pour the lemon curd over the base, giving the tin a gentle shake to even it out. Bake for 15-20 minutes or until almost set, with a slight jiggle in the centre. Allow to cool completely, then place in the fridge for at least 4 hours to set.

6. Scatter with edible flowers just before serving, if using. Slice into pieces using a hot wet knife.

Note: Keeps for 3-5 days covered in the fridge.