1 9-ounce bag fresh baby spinach
3 tablespoons olive oil
1 medium red onion, halved & thinly sliced
1 7-ounce package feta cheese, coarsely crumbled
2 tablespoons Sherry wine vinegar
Place spinach in large bowl. Heat olive oil in heavy large skillet over high heat. Add onion; sauté until brown and softened. Remove skillet from heat and stir in vinegar & return to heat. Add cheese to skillet. Stir to melt cheese slightly, about 1 minute. Season to taste with fresh black pepper. Pour over spinach; toss to coat and wilt slightly.