Preheat oven to 160C (fan forced) and Line a 20×30 brownie pan with baking paper.

In a bowl combine the 1/2 cup caster sugar, coconut, 2 cups gf flour and the melted butter. Stir until the mix resembles damp course breadcrumbs.

Pour the biscuit dough crumbs into the lined brownie pan and press until you have a firm even layer. Make sure to press into the corners so there is no gaps.

Bake on the middle rack of the oven for 25 minutes.

Once cooked remove and allow to cool. Reduce to oven to 140C.

Meanwhile in a clean bowl combine the eggs, egg yolk, remaining caster sugar, zest and mix to incorporate. In a little bowl or cup place the 1/4 cup gf flour and the juice from the lemons and stir until a smooth paste.

Add the lemon paste to the egg mix and stir to mix thoroughly.

If you feel there is lumps in the lemon mix no is the time to sieve the mix. Simple pour it through a fine mesh sieve.

Carefully pour the mix on top of the cooled biscuit base.

Then place on the middle rack of the oven and bake for 30 minutes.

Remove from the oven and allow to cool to room temperature, then place int he fridge to set for 4 hours or over night.

Dust with icing when serving and use a hot clean knife to cut.