Classic Chocolate Mousse for Mud Season

March in New England is not winter and not spring. The snow pulls back from the fields, the back roads turn to soft brown ruts, and every boot in the house leaves a print on the kitchen floor. It is the month that most needs a good dessert, and nothing answers it better than a bowl of real chocolate mousse: dark, cool, airy, and rich enough that a few spoonfuls feel like a small party.

This is the classic method, with nothing clever in it. Bittersweet chocolate is melted with butter, enriched with egg yolks, lightened with whipped cream and then with beaten egg whites. There is only a little sugar, so the chocolate you choose decides almost everything about the result. The work takes about half an hour, and then the refrigerator does the rest.

Choosing the chocolate

Use a bar of bittersweet or semisweet chocolate, not chips. Chips are made to hold their shape in a cookie and contain stabilizers that make them melt thick and set grainy. A bittersweet bar in the range of 60 to 70 percent cacao gives a deep, grown-up mousse. Semisweet, closer to 55 percent, makes it a little sweeter and softer, which is the better choice if children are at the table. Chop it finely so it melts evenly and quickly.

The order of operations

Mousse is three components brought together, and each has its own ideal texture.

1. Chocolate base: melt the chocolate and butter gently over barely simmering water, then let it cool until it feels just warm on your lip, about 95°F (35°C). Too hot and it will melt the cream and deflate the whites. Too cool and it will seize into flecks when the cold cream hits it.
2. Whipped cream: whip to soft peaks that fold over at the tip. Stiff cream makes a heavy, slightly greasy mousse.
3. Egg whites: beat to soft, glossy peaks. Overbeaten whites look dry and clumpy and will never fold in smoothly.

Stir the yolks and sugar into the chocolate first. Then fold in the cream, and finally the whites, in two additions, with a large rubber spatula. Cut down through the center, sweep along the bottom and turn the mixture over, rotating the bowl as you go. Stop as soon as no white streaks remain. A few faint ones are better than a deflated mousse.

A note on raw eggs

Classic mousse uses uncooked eggs, and the eggs are what give it that light, almost foamy texture. For a family dessert with very fresh eggs from a source you trust, many cooks are comfortable with that. For a party, and for anyone pregnant, very young, elderly or with a weakened immune system, use pasteurized eggs in the shell. They are sold in many supermarkets, whip almost as well as regular eggs, and remove the worry. Pasteurized whites take a minute or two longer to reach soft peaks, so be patient and make sure the bowl is spotless.

Keep the finished mousse cold. Like any dish with dairy and eggs, it should not sit out more than 2 hours at room temperature, so bring the glasses out of the refrigerator when you are ready to serve rather than setting them on the buffet at the start of the evening.

From the recipe box

Classic chocolate mousse

About 4 cups, 8 small glasses

Prep

30 min

Cook

10 min

Rest

4 hr

Total

4 hr 40 min

Show amounts in

US cups & spoons metric

Mousse

• 10 oz280 g bittersweet or semisweet chocolate bar, finely chopped
• 4 tbsp57 g unsalted butter, cut in pieces
• 1 cup240 ml cold heavy cream
• 3 extra-large3 extra-large eggs (pasteurized for a crowd), separated
• 2 tbsp25 g granulated sugar
• 1 pinch1 pinch fine salt

To finish

• 1/2 cup120 ml heavy cream, lightly whipped
• 1 oz28 g chocolate, shaved with a vegetable peeler

Method

1. Put the chopped chocolate and butter in a heatproof bowl set over a pan of barely simmering water, with the bowl not touching the water, and stir now and then until smooth, 5 to 8 minutes.
2. Lift the bowl off the pan and let the chocolate cool, stirring occasionally, until it feels just warm, about 95°F (35°C).
3. Meanwhile chill a mixing bowl and beaters, then whip the cream to soft peaks that fold over at the tips; refrigerate it.
4. Whisk the egg yolks and sugar in a small bowl until smooth and slightly paler, about 1 minute.
5. Stir the yolk mixture into the warm chocolate until glossy and even.
6. In a clean, dry bowl, beat the egg whites with the salt until they hold soft, glossy peaks.
7. Fold the whipped cream into the chocolate in two additions until nearly combined.
8. Fold in the egg whites in two additions with a large spatula, stopping as soon as the white streaks disappear.
9. Spoon or pipe the mousse into 8 small glasses or one serving bowl, cover and refrigerate at least 4 hours or overnight.
10. Just before serving, top each glass with a spoonful of lightly whipped cream and a few chocolate shavings.

Notes from the kitchen

• If the chocolate seizes into flecks when the cream goes in, it was too cool; set the bowl over warm water for a few seconds and stir until smooth again.
• Covered mousse keeps 2 days in the refrigerator; add the cream topping on the day you serve it.

Small glasses for a party

A big bowl of mousse looks generous at a family table, but for a party small portions are kinder and easier. Juice glasses, small wine glasses, espresso cups, even little jam jars all work. A 3 to 4 ounce glass holds about half a cup, which is plenty of something this rich.

Spooning mousse into glasses leaves smears on the sides. A cleaner way is to scrape it into a large zip-top bag, snip off one corner and pipe it in. Wipe the rims with a damp paper towel before chilling, and the glasses will look like they came from a pastry case.

Scaling for a crowd

The recipe doubles and triples well, as long as you fold in batches no larger than the biggest bowl you own can handle comfortably. For 24 small glasses, I make three separate batches rather than one huge one, because folding a triple quantity of whites in a single bowl knocks out too much air.

Add half a cup of cream for topping per batch. Everything can be made the day before, and the tray of glasses goes straight from the refrigerator to the table.

Variations

Stir a tablespoon of strong coffee or a tablespoon of orange liqueur into the melted chocolate for a mocha or orange mousse. A spoonful of pure maple syrup in place of the sugar suits the season and gives a faint caramel note. For a spicier version, add a pinch of cinnamon and a tiny pinch of cayenne to the chocolate as it melts.

Serving

Take the glasses out of the refrigerator about 15 minutes before serving so the mousse loses its hard chill and the chocolate flavor comes forward. A thin crisp cookie on the saucer is a good contrast. More desserts for the turning seasons are gathered under The Seasonal Table, and other baking is in Cakes and Baking. For the rest of the monthly dishes, look through the recipe archive. And keep a mat by the door; it is still mud season.