Heat oil in a large saucepan over high heat. Add onion and garlic, cook for 2-3 minutes or until softened. Add beef mince and cook for 5 minutes or until browned, breaking up any large pieces.
Add tomatoes, , stock and herbs, including bay leaf. Cover and simmer for 15 minutes, stirring occasionally. Remove bay leaf.
To make cheese sauce: Melt butter in a saucepan, add flour and stir continuously for 1-2 minutes without browning. Remove from heat and gradually stir in milk. Bring to the boil stirring continuously until sauce thickens. Add cheese and stir until cheese melts.
Grease a 25 x 30cm baking dish. Cover with a layer of lasagne, spread with a 1/3 of the meat sauce and sprinkle with 1/3 of the mozzarella cheese. Repeat to make 2 more layers. Finish with a layer of lasagne sheets. Pour cheese sauce over the top.
Cover with foil and bake in a preheated oven at 180°C for 20 minutes, remove foil and cook a further 10 minutes or until heated through and cheese sauce is a light golden brown.
Sprinkle with extra mozzarella cheese over the cheese sauce in STEP 4 for an extra cheesy top.