MARQUISE au CHOCOLAT

Marquise au Chocolat

Makes 8 to 10 servings

The seventeenth and eighteenth centuries were good times for French pastry chefs. Kings still reigned, aristocrats were scattered around the country, and everyone with a title who could afford sugar and a chef wanted special sweets. It's likely that the Marquise au Chocolat comes from this period. A frozen chocolate mousse, it starts off as a simple sweet, but in the hands of someone's chef, it could become baroque. Even at home, the possibilities for getting fancy with this sweet are just about limitless.

Traditionally, the marquise is packed into a loaf pan, frozen, and then sliced just before serving. This is exceedingly practical, since you can make the dessert weeks ahead; use what you need and keep the rest in the freezer for the next dinner party. The mousse also lends itself to being made in mini loaf pans or even small ramekins — when unmolded, these look very professional.

Similarly, the marquise can be plain or surprising. Often you'll find pieces of Petit Beurre or Biscoff (speculoos) cookies inside it, or the mousse might rest on a cookie or crumb base. Truly, anything that goes with chocolate (and that can stand up to freezing) is fair game for an addition.

A word on the eggs: The yolks in this recipe are not cooked, so it's important to use very fresh eggs, preferably organic and/or from a trusted local source.

1 stick (8 tablespoons; 4 ounces; 113 grams) unsalted butter, cut into 16 pieces

13 ounces (369 grams) bittersweet chocolate, coarsely chopped

4 very fresh large-egg yolks, preferably organic, at room temperature

1/3 cup (67 grams) sugar, plus

3 tablespoons sugar

¼ teaspoon fleur de sel or a pinch of fine sea salt

1½ cups (355 ml) very cold heavy cream

Line an 8½-×-4½-inch or 9-×-5-inch loaf pan with plastic film, leaving some overhang to make unmolding easier.

Put a large heatproof bowl over a pot of simmering water. Drop in the pieces of butter, cover with the chocolate, and heat slowly, stirring occasionally, until the ingredients have melted; don't let the chocolate get too hot. When the chocolate and butter have melted, you should have a thick, velvety mixture. Transfer the bowl to the counter and let cool for 15 minutes.

Working in the bowl of a stand mixer fitted with the whisk attachment, or in a large bowl with a hand mixer, beat the yolks, 1/3 cup of the sugar and the salt at medium speed until the mixture pales and thickens slightly, about 2 minutes. Turn the yolk mixture out onto the chocolate and butter and, with a flexible spatula or a whisk, gently fold together. Don't worry about being thorough now; you're going to fold again soon.

Wipe out the mixer (or mixing) bowl and pour in the heavy cream. Whip the cream until it shows the first sign of thickening, then slowly and steadily add the remaining 3 tablespoons sugar and beat until the cream holds firm peaks. Spoon it onto the chocolate and very gently fold it in.

Spoon the mousse into the prepared pan, pushing it into the corners and smoothing the top. Fold the edges of the plastic film over the mousse and then wrap the pan in more plastic film. Freeze the marquise for at least 6 hours. (The marquise can be frozen for up to 1 month.)

To unmold, unwrap the pan, pull the edges of the plastic film away from the marquise and tug on the plastic to release the marquise. If the marquise is recalcitrant, dip the bottom of the pan in hot water for about 15 seconds, then try again. Turn the marquise over onto a platter or cutting board and serve immediately. (If it's more convenient for you, you can unmold the marquise and return it to the freezer for a few hours before serving.)

Serving: The best way to slice the marquise is to use dental floss or a warm knife--run a long-bladed knife under hot water and wipe it dry. Cut the marquise into slices that are a scant 1 inch thick. If you can serve the slices on cold plates, so much the better. Traditionally the marquise is served with vanilla crème anglaise, a lovely match. If you're rushed for time, you can serve it with faux crème anglaise: melted premium-quality vanilla ice cream. It is also good with whipped cream or crème fraîche.

Storing: Wrapped airtight, the marquise will keep in the freezer for up to 1 

Month