Preheat the oven to 180°C.
In a bowl, mix the lamb with chopped fennel, salt, and pepper. Form small meatballs and set aside.
In a pan, heat olive oil and cook the meatballs until browned on all sides. Remove from the pan and set aside.
In the same pan, sauté chopped red onion and garlic until fragrant.
Add canned tomatoes and beef stock, then bring to a simmer.
In an ovenproof dish, layer the lasagne sheets with the meatballs and tomato sauce, alternating until all ingredients are used.
Top with mozzarella and Parmesan cheese.
Bake in the oven for 25-30 minutes or until the cheese is golden and bubbly.
Serve hot and enjoy!
