Spray a frying pan with some cooking oil spray and cook the onions, garlic, carrot and herbs and fry for a further few minutes, making sure it is all mixed together.
Add the beef mince and cook till browned.
Add the mushrooms, tomatoes, tomato paste, stock and the balsamic vinegar. Bring to a boil, then reduce to low, cover and simmer for approx 30 mins
Peel and slice the sweet potato, sprinkle with some paprika, chilli powder and spray oil and bake in the oven until tender.(approx 30 mins)
When the sweet potato is almost done, you can make the cheese sauce.
Add the milk and cornstarch to a small saucepan over a medium high, constantly stirring until it comes to a boil and thickens. Add the 15g of parmesan cheese and continue to stir until cheese is melted into sauce, season with salt and black pepper.
Using a square lasagne dish. Add half the meat mixture and then 3 lasagne sheets, then layer with the sweet potato slices. Repeat with another layer of meat sauce and then again top with 3 lasagne sheets.
Pour over the top the cheese sauce and sprinkle with the 100g of mozzarella and 15g of parmesan.
Turn oven up to 200c or 400f and bake for approx 30 mins, until cheese has melted and is golden.
