Preheat oven to 180°C.
Grease and line a 20cm springform tin or use a parchment paper sling in an ordinary 20cm cake tin.
Add the flour, sugar, butter and eggs to a food processor and pulse until the mixture just starts to come together - you want it crumbly rather than forming a dough.
Press about ⅔ of the mixture into the base of the tin, reserving the rest for the topping.
For the lemon curd: Add all ingredients to a saucepan and stir over low heat until the butter has melted and the curd has thickened, just below boiling point.
Pour the hot curd over the cake base, then crumble the remaining cake mixture over the top.
Bake for around 30 minutes, or until lightly golden.
Cool completely in the tin before removing.
Dust with icing sugar and serve with cream or vanilla ice cream.
