In separate bowl, mix together egg, vinegar, and water.
Drizzle wet mixture into dry mixture, cutting it in.
Dough will be rough.
Next, roll out the dough on a lightly floured surface and fit into two 9 inch pie pans, crimping the edges.
Bake for 12 minutes at 425 degrees F. Once fully baked, set aside to let cool. Now you can move onto the next steps!
Directions
First preheat your oven to 350 degrees F.
Lemon Filling
In a medium saucepan (I love these non-toxic pans!), whisk together 1 cup sugar, flour, cornstarch, and salt.
Stir in water, lemon juice and lemon zest. Cook over medium-high heat, stirring frequently, until mixture comes to a boil.
Next, gently stir in butter. Place egg yolks in a small bowl (reserving your egg whites) and gradually whisk in 1/2 cup of hot sugar mixture before whisking the egg yolk mixture back into remaining sugar mixture.
Bring to a boil and continue to cook while stirring constantly until thick and semi-translucent.
Remove from heat and pour the filling into your baked pie shell.
Meringue
With a handheld mixer or a stand mixer fitted with a whisk attachment, whip egg whites and cream of tartar together on medium speed for 1 minute, increase to high speed for about four more minutes until soft peaks form.
Add the sugar and salt, then continue beating on high speed until glossy stiff peaks form, about 2 more minutes. Spread meringue on top of filling.
Bake in your preheated oven for 10 minutes, or until meringue is golden brown.