Here are all the colors of a brilliant autumn day. Since sweet potatoes cook more quickly than beets, cut them into thicker slices, which are more likely to keep their shape. The beet greens add a very appealing spinach-like flavor. The pressure cooker tenderized beet skins so much that removing them becomes more a matter of aesthetics than necessity.

Cut the beets from their greens and peel or scrub them. Cut the beets into 1/4 -inch slices and cut the slices in half. Set aside.

Cut and discard the red stems from the beet greens. Rinse the beet green in a sink-full of cold water, taking care to remove all of the sand. Discard any blemished or very large, tough leaves. Drain and chop the beet greens into strips about 2 inches wide. Use about 4 cups of tightly packed chopped greens for the soup, saving the remainder for stock or another use. (They're delicious when sauteed in olive oil with lots of garlic). Cut the peeled sweet potatoes into 1/2-inch slices and cut the slices in half. Set aside. Heat the butter in the cooker. Add 2 Tsp. of the ginger and the onions and cook until the onions are soft, about 3 minutes. Add the beet greens, sliced beets, sweet potatoes, and stock. Lock the lid in place and over high heat bring to high pressure. Adjust the heat to maintain high pressure, and cook for 7 minutes. Reduce the pressure with a quick-release method. Remove the lid, tilting it away from you to allow any excess steam to escape. Stir in the remaining 1/4 Tsp. ginger and the orange zest. Add salt to taste and serve immediately.