There seems to be no consensus on the proportion of liquid to couscous among cooks and in cookbooks. Use the amount of stock that you normally use to make couscous, or follow the package directions.
1 bunch scallions
2 T extra-virgin olive oil
1-1/2 – 2 c diced zucchini
2 c chicken or vegetable stock
2 T lemon juice
1/4 t lemon zest
salt and pepper, to taste
1-1/2 c couscous
1. Separate white parts of scallions from green tops. Chop white parts. Thinly slice green tops. Reserve sliced green tops.
2. In a medium saucepan with a lid, heat the oil over medium heat. Add the chopped white scallion parts and cook, stirring, until softened, about 2 minutes. Add the zucchini and cook, stirring, for another couple of minutes. Add the stock, lemon juice, lemon zest, salt, and pepper; bring to a boil over high heat. Stir in the couscous. Cover and remove from heat. Let stand until all liquid is absorbed, around 7 minutes.
3. Uncover and fluff couscous with a fork. Add the reserved scallion greens and toss well to combine. Serve warm or at room temperature.