Ingredients
1 tablespoon olive oil
1 sweet onion (such as Vidalia), halved and thinly sliced
Coarse salt and ground pepper
1 1/2 pounds mustard greens (2 bunches), stems removed, sliced 1 inch crosswise
2 teaspoons cider vinegar
Preparation
In a large skillet, heat oil over medium-high. Add onion; season with salt and pepper. Cook, stirring frequently, until onion is tender and golden, 6 to 8 minutes.
Add as many greens to skillet as will fit; season with salt and pepper. Cook until wilted, tossing and adding more greens as room becomes available, 2 to 3 minutes. Stir in vinegar; season with salt and pepper, and serve.
