Autumn Soup with Crispy Bacon

Peel sweet potatoes with a vegetable peeler. Cut them in half lengthwise, and then cut them crosswise to make 1/2-inch slices. Peel rutabaga with a small sharp knife and cut into 1/2-inch pieces. Cut 3 slices of bacon into small pieces and place in a medium pot with a cover. Heat gently for a few minutes, until fat is rendered, making sure bacon does not crisp. Add sweet potatoes and rutabagas. Using large spoon, toss vegetables to coat with bacon fat. Cook over medium heat for 2 minutes. Add 5 cups water, 1 teaspoon salt, and 12 black peppercorns. Bring to a boil. Lower heat to medium and cover pot. Cook for 45 minutes, or until vegetables are very soft. Meanwhile, in a nonstick skillet, cook remaining bacon on both sides until just crisp, then place on paper towels to drain. Working in 2 batches, transfer vegetables and cooking liquid to bowl of a food processor. Process until very, very smooth. Return to pot. Add salt to taste and gently reheat. Ladle soup into bowls and crumble crisp bacon on top.