Cream 1/2 cup softened butter and 1/2 cup brown sugar together.
Blend in 1 cup cooked and mashed sweet potatoes and 3 eggs.
Add 1/3 cup corn syrup, 1/2 teaspoon salt, 1/3 cup milk, and 1 teaspoon vanilla extract; mix well.
Pour into unbaked pie shell.
Bake at 425 for 10 minutes; reduce heat to 325 and bake 35 to 45 minutes longer or until well set.