Wash & peel potatoes & boil until tender in salted water. Mash with butter while still hot. Stir in sugar, vanilla, lemon & seasonings. Beat eggs well & combine with milk & coconut. Slowly add milk mixture to sweet potatoes, stirring until well mixed.
Butter a casserole & transfer potato mixture, spreading evenly. Dot the top with an extra tablespoon of butter, if desired.