Crush the chocolate into smithereens in the food processor. Heat the cream and milk until just about boiling, add the vanilla and allspice and pour through the funnel over the chocolate. Let stand for 30 seconds. Process for 30 seconds, then crack the egg down the funnel and process for 45 seconds.
Pour into whatever little cups you're serving in, and sit them in the refrigerator for 6 hours or overnight. But remember to take them out of the refrigerator a good 20 minutes before you want them to be eaten; the chill interferes with their luscious, silky richness.
This makes 2 cups altogether: enough to fill 8 little pots of approximately 1/4 cup capacity. But if you've got only bigger cups, just augment quantities.
Contains Raw Eggs: The Food Network Kitchen suggest caution in consuming raw and lightly cooked eggs due to the slight risk of salmonella or other food-borne illness. To reduce this risk, we recommend you use only fresh, properly refrigerated, clean grade A or AA eggs with intact shells, and avoid contact between the yolks or whites and the shell. For recipes that call for eggs that are raw or undercooked when the dish is served, use shell eggs that have been treated to destroy salmonella, by pasteurization or another approved method.
Recipe courtesy Nigella Lawson, 2007