Julia Child’s chocolate mousse is magic, but you’ll have to work for it

Your arm will get a workout.

But the end result – rich, creamy, chocolaty – will reward you.

Making chocolate mousse from scratch isn’t difficult. It does take a good whisking. You’ll forget all about how tired all that whisking made your arm about four hours later when you remove the finished product from the refrigerator.

Julia Child’s decadent chocolate mousse manages to somehow seem light and airy yet also dense and thick. It’s chocolate magic.

I recently tried her recipe for the first time; it was so delicious I ended up making it twice in the same week. The first time, I couldn’t wait and took it out of the fridge two hours early. Even though it wasn’t completely set, it was still good.

I used electric beaters to whip the egg whites, but whisked the yolks by hand. Only after I made two batches did I watch Julia make the recipe on “The French Chef.” (It’s on YouTube.)

Her technique on the show was slightly different than the written recipe. She used dark rum instead of orange liqueur (I was out of both and opted for bourbon) and added a little cream of tartar to the egg whites. She also demonstrated how to mold and freeze the mousse into a cake-like shape, which she served in slices.

And, while she started to whisk the yolks by hand, she finished the mixture in a stand mixture. That’s just what I plan to do next time.

Julia Child’s Chocolate Mousse

6 ounces (170 grams) bittersweet or semisweet chocolate, chopped

6 ounces (170 grams) unsalted butter, cut into small pieces

1/4 cup dark-brewed coffee

4 large eggs, separated

2/3 cup (170 grams), plus 1 tablespoon sugar

2 tablespoons dark rum (or orange liqueur or bourbon)

1 tablespoon water

Pinch of salt

Heat a saucepan one-third full with hot water, and in a bowl set on top, melt together the chocolate, butter and coffee, stirring over the barely simmering water, until smooth. Remove from heat.

Fill a large bowl with ice water and set aside.

In a bowl large enough to nest securely on the saucepan of simmering water, whisk the yolks of the eggs with the 2/3 cup of sugar, rum, and water for about 3 minutes until the mixture is thick, like runny mayonnaise. (You can also use a hand-held electric mixer.)

Remove from heat and place the bowl of whipped egg yolks within the bowl of ice water and beat until cool and thick. Then fold the chocolate mixture into the egg yolks.

In a separate bowl, beat the egg whites with the salt until frothy. Continue to beat until they start to hold their shape. Whip in the tablespoon of sugar and continue to beat until thick and shiny, but not completely stiff, then add the vanilla.

Fold one-third of the beaten egg whites into the chocolate mixture, then fold in the remainder of the whites just until incorporated, but don’t overdo it or the mousse will lose volume.

Transfer the mousse to a serving bowl or divide into serving dishes, and refrigerate for at least 4 hours, until firm.

Note: I cut the sugar in the yolk mixture to 1/2 cup with good results. The dessert was still decadent but slightly less sweet.

Note: This recipe contains raw or undercooked eggs. The Food and Drug Administration advises that eating raw or undercooked eggs may increase your risk of food-borne illness.