Prepare the Swiss chard, put 2 tender leaves aside, cut the remaining leaves into strips without the coarse stems. Finely dice the onion and clove of garlic. Wash and quarter the cherry tomatoes and remove the stalks.
Heat the butter, add the onion and vegetables and simmer everything for 5 minutes over medium heat. Stir the crème fraîche into the chard sauce and puree everything in the blender. Season with salt, pepper and ginger powder.
Cut the 2 chard leaves into fine strips.
Meanwhile cook the spaghetti, fold into the sauce and serve sprinkled with the tomatoes and chard.