Preheat oven to 375 degrees. Lightly grease an 8-inch square baking dish.
Combine vegetable puree, milk, nutmeg, salt, and pepper in a large bowl. Stir to combine.
Meanwhile, bring a large pot of lightly salted water to a boil. Add pasta and cook about 8 minutes, following package directions. Drain and transfer to bowl with vegetable mixture. Stir in cheddar and ricotta.
Transfer noodle mixture to prepared dish. In a small bowl, combine breadcrumbs, oil and remaining ¼ tsp of salt; sprinkle evenly over noodle mixture.
Cover with foil, and bake 20 minutes. Remove foil, and continue baking until lightly browned and crisp on top, 30-40 minutes more.