Method

1. Preheat the oven to 180°C
2. Melt the 2 tablespoons of butter in a large saucepan over a gentle heat and add the onion, celery, carrot and garlic. Cook until the onion is soft. Add the mince, increase the heat to medium and brown the meat, using a spoon to break up lumps. Season with salt and pepper.
3. Add the passata and beef stock and stir to combine. Simmer on low for 40-45 minutes or until the mixture is reduced and thickened.
4. Meanwhile, in a medium saucepan melt the 50g butter and stir in the flour until it becomes a paste. Add in the milk and whisk to remove any lumps. Simmer on a low heat until the mixture thickens. Season with salt and pepper. Stir through half of the two cheeses.
5. Lightly grease a deep 25cm square baking dish and place a layer of lasagne sheets at the bottom. Spoon over half of the mince mixture and top with one third of the white sauce. Repeat using another layer of lasagne sheet, mince and white sauce.
6. Top with the last of the lasagne sheets and white sauce. Sprinkle over the remaining cheese and bake in the oven for 45 minutes or until the lasagne sheets are cooked and the cheese has turned a golden colour.
7. Serve with seasonal vegetables or side salad.