1 cup lemon huice
1 cup water
1 1/2 cup sugar
5 Tbsp corn starch
1/3 cup lemon zest
Combine first four ingredients in a pot and set over medium high heat.
Whisk for an eternity
When it starts to thicken, add in lemon zest and remove from heat. Move into jars or put cling film over top of the curd and refrigerate. It will thicken some more and set.
NOTE: this makes a lot. So, I put in small jars and freeze. It does affect texture a bit and the liquid separates a bit as it thaws. You can either drain or stir in. If stirred, the curd becomes a more loose consistency.