Preheat the oven to 350 F. Grease then line an 8 inch square pan with parchment paper.

Add the sugar to a bowl and zest the lemons over it. Rub the zest into the sugar using your fingers and thumbs. Add in the salt and the butter.

Use a hand mixer to beat the mixture until light and airy. Add the flour and beat until the mix is in tiny pebbles but when you squeeze it, it holds together.

Press the crust into the bottom of the prepared pan. Use a floured measuring cup to pack it in, into an even layer.

Bake the crust for 20 minutes then remove it and dock it with a fork. Bake for another 15 minutes. While it’s baking..

Blend or process the raspberries into a puree. Press the puree through a fine mesh sieve to discard the seeds. You should have 120g or ½ cup raspberry puree.

Set the sugar in the bottom of a non-reactive pot, I use an enamel coated pot. Zest the lemons over it and rub the zest into the sugar using your fingers until it resembles wet sand.

Add the eggs and lemon juice and whisk immediately. Add the raspberry puree and whisk.

Set the pot over medium low heat and cook, stirring frequently, as the curd thickens. It will thicken first on the bottom, keep stirring until it is thick all over - using an instant read thermometer it should register 155-165 F. Remove from heat.

Set the butter in a glass bowl and a sieve over it. Pour the curd through the sieve then press it through, discarding the zest, egg white bits and raspberry seeds.

Once the crust is golden all over, pour the filling over it. Bake (keeping the temperature at 350 F) for about 10 minutes, until only the center jiggles a bit.

Let cool on the counter until it’s at room temperature then set in the fridge to chill for at least 4 hours but preferably overnight.