This recipe was inspired by Tunisian farfoucha, an aromatic dish of couscous finished with a spicy vegetable stew. Fennel fronds, the feathery greens that grow from the stalks, are a key ingredient in farfoucha—they form a fluffy bed on which the couscous is steamed, then are tossed in after cooking. But since fennel bulbs in U.S. supermarkets often are sold trimmed of their stalks, we sought other ways to infuse anise-like notes into the dish. To create a flavorful base for the sauce, we sauté a thinly sliced fennel bulb with onion and green chili, and we use a generous amount of ground fennel seeds in the couscous. Fresh dill provides grassy herbal notes that hints at fennel. Harissa is a spicy North African pepper paste; its chili heat varies by brand, so you may want to taste your harissa before deciding how much to use.