Directions

1. Gather all ingredients.
2. Preheat the oven to 375 degrees F (190 degrees C). Lightly coat a 3-quart rectangular baking dish with nonstick cooking spray.
3. Bring a large pot of water to a boil. Add pasta and cook until almost tender, about 10 minutes; drain and transfer to a bowl.
4. Heat 2 tablespoons butter and olive oil in the same pot over medium heat. Add onion, celery, and carrots. Cook, covered, until carrots are nearly tender, stirring occasionally, about 7 minutes.
5. Add garlic and cook for 1 more minute.
6. Sprinkle flour over the vegetable mixture; cook and stir for 1 minute.
7. While stirring, slowly pour in broth. Bring mixture to a boil, stirring constantly. Continue to cook and stir until mixture is slightly thickened, 1 minute more.
8. Stir in 1/2 cup Parmesan cheese.
9. Add kale; cook and stir until kale is wilted, 1 minute.
10. Add cooked pasta, meatballs, 2 tablespoons oregano, pepper, and salt to the pot; stir to combine. Transfer mixture to prepared baking dish.
11. To make the topping: Melt remaining 2 tablespoons butter in a bowl. Add panko and stir to combine. Stir in remaining 1/4 cup Parmesan cheese. Sprinkle topping over the casserole.
12. Bake in the preheated oven until golden and heated through, about 20 minutes.
13. Let stand for 10 minutes before serving. Top with remaining 1 tablespoon oregano and the parsley.