1. Preheat the oven to 190°C or 375°F.

2. Cook the spaghetti according to package instructions until al dente then set it aside.

3. In a large mixing bowl combine the ground beef egg breadcrumbs flour salt black pepper oregano and a pinch of paprika. Mix well with your hands until just combined do not overmix.

4. Use your hands to shape the mixture into meatballs about 3.8 cm or 1 1/2 inches in diameter. Place them on a baking sheet lined with parchment paper.

5. Melt 15g or 1 tablespoon of butter in a large skillet over medium heat. Once melted add the diced onion and cook until softened about 5 minutes. Add the meatballs and cook until browned on all sides about 5-7 minutes.

6. Add the vegetable broth cube to the skillet scraping the bottom of the pan to release any browned bits. Stir in 240ml or 1 cup of milk and bring the mixture to a simmer. Let it cook for 5 minutes stirring occasionally until the sauce has thickened slightly.

7. In a separate saucepan melt the remaining 15g or 1 tablespoon of butter over low heat. Stir in 15g or 1 tablespoon of flour to make a roux cooking for 1 minute. Gradually add 115g or 1 cup of grated cheese stirring until smooth and creamy. Season with salt black pepper and a pinch of cayenne pepper.

8. In a large mixing bowl combine the cooked spaghetti meatballs and creamy cheese sauce. Mix well to combine.

9. Transfer the spaghetti mixture to a 23cm x 33cm or 9x13-inch baking dish and top with the remaining grated cheese.

10. Bake in the preheated oven for 20-25 minutes or until the top is golden brown and the gratin is hot and bubbly.