Preheat your oven to 350 degrees. Place the tart shells in the oven for 3-5 minutes to crisp up the
edges.
Add the egg whites to a glass bowl and use a mixer to beat until frothy.
Add the cream of tartar. Add the sugar a little at a time while constantly beating the egg whites. Continue to beat until stiff peaks form, about 7-10 minutes.
Fill the pastry shells to the top edge with the lemon curd.
Use a piping bag to top the pastry shells with the meringue.
Use a kitchen torch to toast the outside of the meringue. Don't get the kitchen torch too close or the meringue will burn.
If you don't have a kitchen torch, you can toast the meringue under the broiler, just be sure to watch it closely so it doesn't burn.
The recipe can be easily adjusted to make as many tarts as you need.
You can substitute brown sugar for the granulated sugar.
You can substitute white vinegar or lemon juice for the cream of tartar to help stabilize the egg whites.
Make sure there are no pieces of shell or yolk in your egg whites - this can cause the meringue to not whip up properly.
Separate the whites from the yolks when the eggs are still cold - it is easier this way and they separate cleaner
Let them whites come to room temperature
Use cream of tartar
A clean, dry glass or ceramic bowl will work the best.