Clean and peel the squash and cut into thick rounds, at least an inch thick. Coat a cookie sheet with olive oil. Lay each round on the sheet and flip it so that there is a film of olive oil on top. Roast the squash at 400 for about 25 minutes and flip. Continue roasting until it’s fork tender. Allow to cool enough to handle.In enough oil to coat the bottom of the soup pot well, sauté cardamom and cumin for a minute, then add the onions and garlic and sauté for about 3 minutes. Add the collards, chick peas and vegetable broth and just enough water to cover the greens. Simmer until the greens are tender enough. Cut the squash into large chunks and add them to the stew. Heat through and serve.