- Preheat the oven to 180ºc.
- Cover a 9 x 13 inch baking tray with baking parchment. Leave an overlap and grease the parchment also.
- Place the dry ingredients for the crust into a food processor and pulse to combine.
- Add the cold butter and mix until it resembles coarse breadcrumbs around 10 seconds.
- Pour the mixture into the prepared pan and press down. A measuring cup works well for pressing it flat and even.
- Place in the fridge for 30 minutes or into the freezer for 15 minutes.
- Bake in the oven for 15-20 minutes until the crust is golden.
- Now to make the filling. In a large bowl whisk together the eggs, sugar, lemon juice, lemon zest and flour.
- Remove the crust from the oven.
- Pour the lemon mixture the top of the cooked base and immediately place the pan back into the oven and bake for a further 30-35 minutes until the topping is firm and set.
- Allow to cool completely in the tin.
- Once cooled using the overhang of parchment paper, lift out of the tin.
- Cut into squares or triangles then dust with icing sugar.
- Can be kept in an airtight container for four days in the fridge.
- Can be frozen for three months.