I have an old recipe from a 1966 Better Homes & Garden book. It's a "slipped" custard pie. The crust is baked by itself and the custard by itself. Then the custard is slipped into the crust. No more soggy crust.
CUSTARD PIE: Blend 4 slightly beaten eggs, 1/2 cup of sugar, 1/4 teaspoon salt and 1/2 teaspoon vanilla. Gradually stir in 2 1/2 cups milk (scalded). Pour into unbaked 9" pastry shell. Sprinkle with nutmeg. Bake at 350* for 35-40 minutes or until knife comes out clean. Cool on rack.
SLIPPED CUSTARD PIE: Make and bake pastry shell first and let cool while making custard. Prepare filling for custard pie. Place buttered pie plate in a shallow baking pan. Pour custard in pie plate. Fill baking pan with cold water(about an inch or so). Bake at 350* for 35-40 minutes or until knife comes out clean.Cool on rack. When custard is cool, carefully run a spatula around edge. Shake plate gently to loosen custard. Hold custard just above far rim of baked pastry shell; gently slip into shell. Chill. It's a little hard to slip, but worth it.