In a large bowl, combine eggs, sugar, salt and vanilla. Mix just enough to incorporate all the ingredients. Set aside. In a medium saucepan over medium-high heat, combine milk and butter. Use a wire whisk and stir constantly until the milk begins to rise in the saucepan at a rapid boil - 5 to 8 minutes. NEVER stop stirring, or the milk will burn. Pour the hot mixture into the egg mixture, stirring as you pour.
Line a 9 inch pan with dough. Pour custard mixture into crust. Protect the edges of crust with a ring of aluminum foil.
Bake in the preheated oven for 20 minutes. Remove foil and bake for 8 to 10 minutes. Filling will appear slightly jiggly. Allow to cool.
