The stems are removed, diced and set aside. The leaves are blanched in boiling salted water for 3 minutes and then shocked in ice water. This helps them to maintain their color when further cooked.
The diced chard stems and diced onions are sauteed in olive oil until the onions become slightly translucent. The walnuts and raisins are added and cooked for about 5 minutes. A splash of sherry vinegar goes in followed by the blanched and drained chard.
Saute the greens for a minute and add some chicken or vegetable stock. Cook for about three minutes more, plate and serve.