In a large heavy saucepan, combine the eggs, 1 cup of cream, 1 cup of milk and sugar. Cook and stir over medium heat until thick enough to coat the back of a spoon (about 160 degrees F). Be sure to stir constantly and watch not to boil or the eggs will curdle.
Pour into a large bowl and add in remaining cream and milk. Stir in nutmeg, vanilla and peppermint schnapps if so desired. Cover and refrigerate immediately. Best if left to refrigerated overnight.