Rinse the Swiss chard thoroughly to remove dirt
Trim off the tough ends of the stems
Separate the stems from the leaves if desired
Chop the stems into small pieces
Chop the leaves into large pieces
Heat olive oil or butter in a skillet over medium heat
Add minced garlic or onion if desired
Add the chopped stems first and cook until slightly tender
Add the leaves and cook until wilted
Season with salt and pepper
Add lemon juice, vinegar, or red pepper flakes if desired
Serve warm as a side dish or mix into other dishes