Discard coarse stems of spinach. Wash spinach thoroughly and drain. Working in batches, stack leaves on top of one another and cut into 1/2-inch-wide strips.
In a large heavy skillet cook shallots in oil over moderate heat, stirring, until softened. Add spinach and salt and pepper to taste and saute over moderately high heat, stirring, until wilted and tender, about 3 minutes.
