How to Make It
In a large, deep skillet, cook the bacon in the oil over moderately high heat, turning once, until crisp, about 6 minutes. Drain the bacon on paper towels, leaving the fat in the skillet. Coarsely chop the bacon.
Add the onion and garlic to the skillet and cook over moderate heat, stirring occasionally, until softened and lightly browned, about 6 minutes. Add the kale, season with salt and pepper and toss until slightly wilted. Stir in the vinegar, cover and cook over high heat until the kale is tender, about 5 minutes. Stir in the chopped bacon and serve.