1. Peel and chop the onion.
2. Heat 2 tablespoons of olive oil in a pan.
3. Sauté the onion until translucent.
4. Add the ground beef and cook for 5 minutes.
5. Add the crushed tomatoes, salt, and pepper, and simmer for 20 minutes.
6. Preheat the oven to 200°C (400°F).
7. Drain and grate the mozzarella.
8. Place a layer of lasagna sheets in the bottom of a baking dish, then cover with the beef mixture.
9. Next, add the mozzarella and sprinkle with Parmesan cheese.
10. Finish by covering with heavy cream.
11. Repeat the process by layering lasagna sheets, beef mixture, mozzarella, and Parmesan cheese until all the ingredients are used.
12. Season with salt and pepper if needed.
13. Bake for about 25 minutes.
14. Enjoy straight out of the oven.