Use only very ripe paw paws, when skin is black or nearly so; remove skins and seeds with a knife, then process pulp in blender until smooth. Prepare pastry for 1 crust pie; preheat oven to 425 degrees. Blend together sugar, salt, nutmeg, and flour; combine with eggs, paw paws, vanilla, and evaporated milk, stirring until well blended. Pour into prepared pastry shell. Bake 15 minutes in preheated oven. Reduce heat to 350 degrees; bake about 30 minutes longer or until knife inserted comes out clean.