Preheat oven to 300 degrees F (150 degrees C). Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
Meanwhile, in large skillet, saute chile pepper, bell pepper and onion until soft. Add tomatoes, puree and chili powder and cook 2 minutes more. For a smooth sauce, puree with a hand blender, or puree in batches in food processor.
Combine pasta and sauce in 9 x 13 baking dish and bake for 15 minutes. Serve hot.