1 cup quinoa
1/2 small white onion, finely chopped
1 celery rib, cut into 1/4-inch dice
1 carrot, cut into 1/4-inch dice
1 small fennel bulb (sometimes called anise), trimmed, cored, and cut into 1/4-inch dice
1 1/2 cups water

Rinse quinoa in a bowl in at least 5 changes of water, rubbing grains and letting them settle before pouring off water, until water runs clear. Drain in a fine sieve. Cook onion, celery, carrot, and fennel in a little stock in a 3-quart heavy saucepan over moderate heat, stirring occasionally, until onion is softened and stock is nearly gone, 5 to 6 minutes. Add quinoa and sauté over moderately high heat, stirring, until lightly toasted, 2 to 3 minutes. Add water and pepper to taste and cook over moderately low heat, covered, until quinoa is tender and liquid is absorbed, 12 to 15 minutes.