1. In a skillet, heat oil over medium heat. Add onions, carrots and celery and cook, stirring, until carrots are softened, about 7 minutes. Add garlic, ginger, salt and peppercorns and cook, stirring, for 1 minute. Add tomatoes with juice and bring to a boil. 2. Transfer to slow cooker stoneware. Add sweet potatoes, tofu and vegetable stock and stir well. Cover and cook on low for 5 hours or on high for 2 1/2 hours, until hot and bubbly. 3. In a bowl, combine peanut butter, lime juice, soy sauce and red curry paste. Mix well. Add to slow cooker stoneware and stir well. Add coconut milk and red pepper and stir well. Cover and cook on high for 20 minutes, until pepper is tender and mixture is hot. Garnish with peanuts and cilantro.