Preheat the oven: Preheat your oven to 180°C (350°F) and lightly grease a 9x13 inch baking dish.

Cook the pasta: Bring a large pot of generously salted water to a boil. Add the Stellini pasta and cook until al dente according to package directions. Drain thoroughly and set aside.

Brown the meat: Heat the vegetable oil in a large skillet over medium-high heat. Add the chopped onion and minced garlic, sautéing for 2 minutes until fragrant and softened. Add the ground meat, breaking it apart with a wooden spoon. Cook until completely browned and no pink remains.

Add tomato sauce: Drain any excess grease from the meat. Season generously with salt, pepper, and your preferred meat seasoning. Pour in the tomato sauce, stir well, and let it simmer on low heat for 2-3 minutes. Remove from heat.

Make the béchamel: In a separate medium saucepan, melt the butter over medium heat. Whisk in the flour and cook for 1 minute to form a paste. Gradually whisk in the milk, pouring slowly to prevent lumps. Continue to whisk gently until the sauce thickens and coats the back of a spoon. Remove from heat and stir in a pinch of salt and the nutmeg.

Assemble the casserole: In your prepared baking dish, spread exactly half of the cooked pasta. Top with half of the meat sauce, followed by half of the creamy béchamel. Repeat these three layers once more.

Add cheese and bake: Sprinkle the freshly shredded mozzarella evenly over the top of the casserole. Place in the preheated oven and bake for 20 minutes, or until the cheese is melted, bubbling, and golden brown around the edges.

Rest and serve: Remove the pasta from the oven and let it rest for 5 minutes before slicing and serving. Enjoy!