Preheat oven to 180°C and grease an ovenproof dish.
Brush the aubergine on both sides with butter and cook in a non-stick frying pan in a single layer, for 1 - 2 minutes each side or until tender and golden.
Repeat until all of the aubergine is cooked.
Heat the oil in a pan and cook the garlic for 30 seconds, add t he peppers and mushrooms and continue cooking for 4 - 5 minutes.
Add the tomato mix and tomato paste and cook for 4 - 5 minutes or until reduced.
Season to taste with salt and pepper and set aside.
Finely chop the drained spinach and put into a clean mix ing bowl. Stir in the sour cream and feta cheese.
Place a single layer of the aubergine on the base of an ovenproof dish.
Top with half of the tomato mixture and half of the lasagna sheets, spread in a single layer.
Top with all of the spinach mixture, another layer of aubergine, the remaining tomato mixture and a last layer of lasagne sheets.
Top with the white sauce and Tussers Cheese.
Cover with foil and bake for 20 minutes.
Uncover and bake for a further 20 - 25 minutes or until golden and cooked through.