Preheat oven to 350°F.
Bring a large pot of water to a boil. Add pasta and cook until almost al dente. Drain and set aside.
In the meanwhile, heat oil in a large saucepan over medium heat. Add onion and sauté until translucent, approximately 5-7 minutes. Add garlic and cook until fragrant, 2 minutes. Add mushroom and kale and cook for 5-7 minutes, or until slightly cooked down.
In a lightly greased 9 x 13 baking dish, add the cooked pasta. Add the kale mixture, pumpkin, egg, tomato sauce, ricotta cheese, and basil. Stir everything together until well-combined. Top with mozzarella.
Cover with aluminum foil or baking mat and bake for 25-30 minutes. Remove from oven and serve warm.
