Red butter lettuce is slightly sweet, vibrant, and has a smooth, buttery texture. It’s low in calories, with just around 10 calories per cup of shredded lettuce, and is a good source of vitamin A, vitamin C, folate, and some iron. Add a leaf to a sandwich; mix with a crunchy lettuce such as radicchio or endive for a beautifully textured salad; use as a bed for grilled or broiled meat or fish.