Separate the Swiss chard stems from the leaves using a sharp knife. Chop the stems into ¼-inch pieces. Chop the leaves roughly. Crush the garlic cloves.
In a non-stick pan, heat a drizzle of oil on MEDIUM. Add the garlic and Swiss chard stems. Sauté for 1–2 minutes. Add the chard leaves. Sauté for another minute.
Squeeze the lemon juice over the Swiss chard. Lightly season with a pinch of salt and pepper. Sauté for another minute.