Heat the ghee, butter or oil in a large saucepan and saute then onion for a few minutes until slightly softened.
Add the garlic, and carrots and saute for a few minutes more before adding the mushrooms and pepper.
When the vegetables are all slightly softened, add the beef and cook until browned, breaking it up and mixing every few minutes.
Add the tinned and fresh tomatoes (or passata), tomato puree and oregano and give it all a good stir.
Bring the mixture to a boil, then reduce and simmer for anywhere from 20 minutes to an hour and a half.
Meanwhile, preheat the oven to around 190oC and prepare your aubergine and cheese.
When the sauce is ready, begin to layer the lasagne in a baking dish starting with a layer of sauce, then some thin slices of aubergine and a handful of cheese. Repeat this and end with some cheese on top.
Bake the lasagne in the oven for around 25-30 minutes.