Instructions

1. First, you will want to assemble and blind-bake your crust. This will allow your crust to keep its shape and prevent bubbling. It will also help keep the crust from getting soggy.
2. After your pie crust is ready, preheat the oven to 350 degrees Fahrenheit, and prep all of the ingredients so that you can work quickly at the stove.
3. Next, we will prepare the meringue. In your stand mixer, you will whisk the egg whites on low until it is nice and frothy. Then, you will add in the cream of tartar and slowly add in the sugar. You can increase the speed to medium. Continue to beat until you have stiff peaks. When you lift up the beater, you will see these stiff peaks stay suspended in the air.
4. Once you have the stiff peaks, you can move on to the custard.
5. In a medium saucepan, whisk together the granulated sugar, all-purpose flour, cornstarch, and salt. Then, add in the water, lemon juice, and lemon zest. Bring the mixture to a boil over medium heat, stirring frequently.
6. Once it is boiling, add the butter to the saucepan and mix well until it is melted.
7. Working quickly, in a small bowl, whisk together the egg yolks. Remove a 1/2 cup of the hot sugar mixture and add to the egg yolks and whisk together well.
8. Add the egg yolk-sugar mixture back into the saucepan, and whisk consistently. Bring the mixture back up to a boil, and whisk for one minute while it is boiling. The mixture has turned into a custard and should be very thick and creamy.
9. Carefully pour the custard into the pie crust in an even layer. Be sure not to burn yourself! The custard will be very hot.
10. While the custard is still hot, gently fold the meringue onto the top of the pie. Spread the meringue all the way over the edge of the crust so that the custard does not show through. Use a rubber spatula to create swirls on top of the meringue.
11. Bake for 10 minutes, or until the top of the meringue is a golden brown.
12. Allow to cool for an hour, and then refrigerate for four hours to cool and set completely.