2 bunches swiss chard, well rinsed, center ribs discarded and leaves cut widthwise into 1-inch pieces
1 tablespoon balsamic vinegar
Toast almonds in a large non-stick skillet over medium heat, stirring frequently, until golden, 3 to 5 minutes; set aside.
Heat oil in the skillet over medium heat. Add onions and sauté until they softened and begin to brown, about 3 minutes. Add chard and stir until it is wilted, about 5 minutes. Add vinegar and almonds. Serve immediately.