Preparation of Iced Mousse with Cream

Ingredients

Equipment Needed

• •Small heavy-bottomed saucepan
• •Heatproof mixing bowl
• •Flexible spatula
• •Fine-mesh sieve
• •Digital instant-read thermometer
• •Electric hand mixer or large balloon whisk
• •Wide bowl for the ice bath
• •1-quart (1-litre) metal loaf tin or freezer-safe mould
• •White baking parchment

Instructions

1. 1

   Prepare the mould

   Line a 1-quart (1-litre) loaf tin or freezer-safe mould with white parchment, leaving enough overhang to cover the surface later. Chill the lined mould. Fill a wide bowl halfway with ice and cold water, and make certain the filled mould will sit level in the freezer before the mixture is ready.

   A metal mould freezes the mousse more evenly than thick glass. The parchment replaces the original white paper and makes unmoulding clean without changing the preparation.
2. 2

   Cook the crème anglaise

   Whisk the yolks with the powdered sugar in a heatproof bowl until perfectly smooth and slightly pale, but don't beat them into a foam. Warm the milk in a small heavy saucepan until tiny bubbles gather around its edge. Pour one-third of the hot milk into the yolks while whisking, then whisk this mixture back into the remaining milk. Cook over low heat, stirring constantly with a flexible spatula, until the crème anglaise reaches 180 to 183°F (82 to 84°C) and nappes the spatula, coating it so a finger drawn through leaves a clean path. Never let it boil. If the first fine grains appear, remove the pan immediately, whisk in 1 tablespoon of the measured cold cream, then blend briefly and strain. Ça se rattrape. Solid scrambled curds have gone too far, so watch the edge of the pan closely.

3. 3

   Chill it stone cold

   Strain the crème anglaise into a clean bowl and set it over the prepared ice bath. Stir slowly until no warmth remains, replacing melting ice as needed. Cover the surface and refrigerate until the custard is cold through, ideally 40°F (4°C) or below, about 45 minutes. Mere coolness isn't enough. Warm custard loosens the cream and lets every bubble escape.

4. 4

   Add cream and flavour

   Return the bowl of cold crème anglaise to a fresh ice bath and pour in the remaining chilled cream. Start the hand mixer on low, then sift the tragacanth into the moving liquid in a fine, steady rain so it cannot gather into lumps. If using xanthan, add only the smaller quantity given. Mix in the vanilla. For a fruit mousse, omit the vanilla unless it suits the chosen fruit and add the cold strained purée now, preserving the source formula's equal-volume proportion. Let the mixture stand over ice for 5 minutes so the gum can hydrate. If small lumps remain, blend for 10 seconds and strain the mixture while it is still cold.

5. 5

   Whisk over ice

   Whisk over the ice bath at medium-high speed for 6 to 10 minutes, turning the bowl occasionally so every part stays cold. The preparation is ready when it has increased by roughly one-third, holds a mass of fine bubbles, and leaves a soft track behind the whisk. You want abundant froth, not stiff whipped-cream peaks. If little happens after 3 minutes, the mixture is too warm. Stop, refrigerate it for 15 minutes, renew the ice bath, and begin again. Never try to overcome warmth with faster whisking.

6. 6

   Mould and freeze

   Spoon the frothy mixture into the chilled mould without pressing out its air. Smooth the top lightly, fold over the parchment, and seal the mould tightly with its lid or two snug layers of food wrap. Freeze until firm through the centre, about 3 hours in four small moulds or 4 hours in one large mould. A loose covering encourages icy edges, so close it thoroughly as the source directs.

7. 7

   Unmould and serve

   Transfer the mousse to the refrigerator for 10 minutes before serving. Unwrap it, invert it onto a chilled platter, and peel away the parchment. If it clings, hold a warm damp towel against the outside of the mould for 5 seconds, then try again; prolonged heat melts the fine outer bubbles. Cut with a warm, dry knife or serve with a broad spoon. If the mousse has frozen very hard overnight, give it another 10 minutes in the refrigerator. À table!

Chef Tips

• •Use only food-grade gum tragacanth. It is the stabilizer in the source formula and gives the frozen mousse a short, creamy melt. Xanthan is stronger, so never substitute it measure for measure; ¼ teaspoon (1.25 ml / 0.8 g) is enough for this batch, though its finish will be slightly slicker.
• •The formula has been reduced to one-quarter of the brigade quantity without changing its proportions: four yolks, equal volumes of milk and cream, and the corresponding quantities of sugar and tragacanth. Reduce the amounts, never the technique.
• •For a fruit mousse, choose a purée with enough character to survive freezing. Raspberry, apricot, peach, or strawberry all work when strained smooth. Outside the season, unsweetened frozen fruit picked ripe is more honest than tired fresh fruit; thaw it, purée it, strain it, and chill it completely.
• •Don't whip the cream separately. The source adds it raw, meaning fluid and unwhipped, before the entire preparation is whisked over ice. Separate whipping produces a semifreddo-like texture and changes the method.
• •Cold dulls flavour and sweetness. Taste the mixture immediately before whisking; the vanilla or fruit should seem a little more pronounced than you want at the table, because freezing will quiet it.

Advance Preparation

• •The crème anglaise can be cooked, strained, and refrigerated up to 1 day ahead. Cover its surface directly and keep it thoroughly cold before adding the cream.
• •The complete mousse can be moulded and frozen up to 3 days ahead. Seal it carefully so it doesn't take on freezer aromas or develop icy edges.
• •For the cleanest texture, move the mousse from freezer to refrigerator 10 to 20 minutes before unmoulding, depending on the depth of the mould.

Frequently Asked Questions

Nutrition Information

1 serving (about 120g)