In a small bowl whisk together the rum, egg, and molasses. Pour into a tall heat-proof drinking vessel (like a glass beer mug) and set aside. To a small saucepan set over low heat, add the ale and gently bring to a low simmer. When the ale is heated through, gently pour over the rum-egg mixture in the glass, then pour the same mixture back into the saucepan. Continue pouring back and forth to create a frothy consistency, ending with a final pour back into the glass. Top with a bit of freshly grated nutmeg and drink.
Kill-Devil. Oh be Joyful. Rumbullion. Demon Rum. There were as many names for the spirit as there were ways to drink it. Rarely consumed plain – or neat as we say today – rum was often combined with all manner of tonics including spring water, citrus juices, freshly grated spices, small and dark beers, warmed through with cream, hot butter, or whipped into a frenzy with eggs.