1. Prepare a large ice bath, and set aside. Fill a medium saucepan with 2 inches water. Set over medium heat, and bring to simmer.

2. In a large stainless-steel bowl, whisk together egg yolks, salt, and sugar until very pale. Add the Muscat; whisk to combine.

3. Place bowl over a pan of simmering water, and whisk until mixture has thickened and has tripled in volume, 8 to 10 minutes. Remove mixture from heat, and immediately transfer to ice bath. Whisk until chilled.

4. In a large chilled bowl, whip cream until soft peaks form. Add the lemon juice, and fold the whipped cream into the chilled sabayon. Divide among 12 serving dishes; top each with 2 roasted chestnuts and 1 chocolate straw; sprinkle with cocoa. Serve.