The secret here is gently cooking the custard base, giving you a rich, velvety texture and total peace of mind. You'll whisk milk, sugar, and eggs on the stove until perfectly thickened, then chill the mixture until it's icy cold. Right before serving, fold in freshly whipped cream and a splash of light rum for a festive finish. It's a comforting holiday classic that beats the store-bought cartons every time.