The Ultimate Lemon Mousse
2 tablespoons water
1 teaspoon plain gelatin
1/2 cup (1 stick) unsalted butter
3/4 cup sugar
3 tablespoons finely grated lemon zest
1/2 cup fresh lemon juice
6 large egg yolks
3/4 cup heavy cream
Pour the water in a small bowl, sprinkle the gelatin over the water, and let
stand about 10 minutes, or until softened. Put the bowl in a larger bowl of hot
water, and stir until the gelatin has dissolved and the liquid is clear.
Meanwhile, melt the butter in a large heavy pan over medium-low heat. Remove the
pan from the heat and whisk in the sugar, zest, lemon juice and salt. Whisk in
the yolks until smooth. Cook the mixture, stirring constantly, until it thickens
and leaves a path on the back of a wooden spoon when a finger is drawn across
it; do not allow the mixture to boil.
Remove the pan from the heat, stir in the gelatin mixture and immediately pour
through a strainer into a bowl. Let cool to room temperature, whisking
Beat the cream with an electric mixer on high speed in a large bowl just until
the cream forms stiff peaks. Add the cream to the lemon mixture in 3 batches,
gently folding it in with a whisk.
Divide the mousse evenly between 4 stemmed glasses. Refrigerate, loosely
covered, for at least 2 hours or up to 2 days, until set and thoroughly chilled.