Notes: Preserved lemons are available in gourmet food stores. If you can't find them, use 2 teaspoons grated lemon peel and 3 tablespoons lemon juice.
In a 1 1/2- to 2-quart pan over high heat, bring broth to a boil. Stir in couscous and preserved lemon. Cover, remove from heat, and let stand 5 minutes. Fluff couscous with a fork and serve.