In a small bowl whisk together ½ cup sugar, cornstarch and egg until well combined then set aside.
In a medium saucepan bring the lemon juice, remaining ½ cup of sugar and lemon zest to a boil. Reduce the heat to low then slowly whisk in the egg mixture. Continue to cook on low and whisk until it begins to thicken.
Remove from heat and pour into a small bowl. Cover with plastic wrap and cut a slit in the top to release the heat while it cools to room temperature.
Preheat the oven to 350 F. Spray six mini tart dishes with cooking spray and set aside.
Dust a flat, clean surface with flour then roll out the dough to about ¼ inch thick. With a small bowl or large cookie cutter, cut out circles that are slightly larger than the tart pans. Carefully fit the circles into the tart pans, pressing down on the edges and removing excess dough.
Use a fork to make air holes in the bottoms of each tart then cut a small piece of parchment paper to rest over the top. Fill each with pie weights, beans or rice then bake for 20 minutes in the oven.
Allow to cool then remove pie weights and parchment paper. When the lemon curd has cooled and thickened, spoon into each tart crust. Refrigerate for at least another hour then serve.