1. Preheat your oven to 190°C/375°F.

2. In a large mixing bowl, combine 450g/1 lb of ground beef, 1 medium chopped onion, 2 cloves of minced garlic, 1 egg, 60g/2.1 oz of breadcrumbs, 15g/0.5 oz of chopped parsley, 15g/0.5 oz of chopped basil, 1 teaspoon of salt, and 0.5 teaspoon of black pepper.

3. Mix the ingredients well with your hands or a wooden spoon until they are just combined. Be careful not to overmix.

4. Use your hands to shape the mixture into meatballs, about 3.8 cm/1.5 inches in diameter.

5. Place the meatballs on a baking sheet lined with parchment paper, leaving a little space between each meatball to allow for even cooking.

6. Bake the meatballs in the preheated oven for 18-20 minutes, or until they are cooked through and lightly browned on the outside.

7. While the meatballs are baking, prepare the cheese sauce.

8. In a medium saucepan, melt 30g/2 tablespoons of butter over medium heat.

9. Add 30g/2 tablespoons of flour and whisk together to make a roux, cooking for 1-2 minutes.

10. Slowly pour in 240ml/1 cup of milk, whisking constantly to avoid lumps.

11. Bring the mixture to a simmer and cook for 2-3 minutes, or until it thickens and coats the back of a spoon.

12. Remove the saucepan from the heat and stir in 120g/0.5 cup of grated mozzarella and 60g/0.25 cup of grated Parmesan cheese until melted and smooth.

13. Season the cheese sauce with salt and black pepper to taste.

14. In a large skillet, combine the baked meatballs and cheese sauce.

15. Simmer the mixture over medium-low heat for 5-7 minutes, or until the meatballs are well coated in the cheese sauce.

16. In a 23x33 cm/9x13-inch baking dish, create a thin layer of the cheese sauce.

17. Arrange 2 lasagna sheets on top of the sauce.

18. Spoon half of the meatballs and cheese sauce mixture over the lasagna sheets.

19. Sprinkle with half of the grated mozzarella and Parmesan cheese.

20. Repeat the layers, starting with the cheese sauce, lasagna sheets, meatballs and cheese sauce mixture, and finally the remaining grated mozzarella and Parmesan cheese.

21. Cover the baking dish with aluminum foil and bake in the preheated oven for 25-30 minutes, or until the lasagna is hot and the cheese is melted and bubbly.

22. Remove the aluminum foil and bake for an additional 5-10 minutes, or until the top is lightly browned.

23. Remove the lasagna from the oven and let it rest for 10-15 minutes before serving.

24. Serve hot and enjoy!