Carrageen moss contains a natural gelatin that is used as a thickener in many commercial food products. Note that the pudding is only faintly sweet. For an "egg-safe" version, substitute pasteurized eggs in the recipe.
1⁄4 oz. (about 1⁄2 cup) dried carrageen moss
3 cups milk
3⁄4 cup heavy cream
1 vanilla bean
Wide strips of zest from 1 lemon
2 eggs, separated
1 tbsp. superfine sugar
1. Put carrageen into a medium bowl, cover with lukewarm water, and let soak for 15 minutes. Drain well through a fine sieve.
2. Put carrageen, milk, cream, vanilla bean, and lemon zest into a small pot and bring to a boil over medium-high heat. Reduce heat to medium-low and simmer, stirring occasionally, until thickened, about 30 minutes. Strain milk mixture through a fine sieve set over a medium bowl. Push all of the natural gelatin from the carrageen through the sieve with the back of a spoon, discarding any solids that are left. Put the egg yolks and sugar into a medium bowl and whisk until pale and frothy, 1–2 minutes. Slowly pour the milk mixture into the yolk mixture, whisking rapidly to combine. Set aside.
3. In another medium bowl, whisk the egg whites with a clean whisk until stiff peaks form. Fold the egg whites into the egg yolk–milk mixture, stirring gently to break up any lumps.
4. Divide pudding among six small 3/4-cup glasses, cover with plastic wrap, and refrigerate until set and chilled throughout, about 3 hours. Serve cold.