Heat the oil in a large frying pan and sear the steak pieces. Season with salt and pepper.
Add the peppers and onions and cook until the moisture has evaporated and they begin to get some colour, then add the garlic and cook for a further few minutes to soften.
Grease a deep sided lasagna dish and pour a layer of the bechamel into the bottom, then top with lasagna sheets, a layer of the pepper steak mix, slices of provolone and more bechamel. Repeat to the top of the dish and finish with a layer of bechamel.