Heat olive oil in a medium saucepan over medium heat.

Cook chopped shallots until soft but not browned, about 4 minutes.

Add sliced sweet potato, ground sumac, and Israeli couscous to the saucepan.

Cook, stirring constantly, until the couscous starts to toast, about 2 minutes.

Pour in chicken or vegetable stock, and add salt and pepper to taste.

Bring the mixture to a boil, then cover the saucepan and reduce heat to low.

Simmer the couscous for 10-12 minutes, or until all the liquid is absorbed and the couscous is al dente.

Remove the saucepan from heat and let it stand, covered, for 5 minutes.

Fluff the couscous with a fork before serving.