First of all, put the fish fillets in your oven and bake by following the instructions on the pack.
While the fillets are cooking, you can heat the olive oil in a saucepan and fry off the crushed garlic, spring onions, diced peppers and chopped rosemary.
Now add the chopped tomatoes, sundried tomato paste and vinegar. Simmer the mixture for 5 minutes, adding a pinch of salt and pepper to taste.
To make the cheese sauce, simply put a knob of butter in a saucepan on a low heat.
Add the flour and mix vigorously until you make a smooth paste. Now add the milk little by little and bring the mixture to the boil, stirring continuously until thick and smooth
Take the mixture off the heat, add the grated cheese and stir until it has melted away.
The breaded fish should be cooked through by now, so spread about half of the tomato and pepper mix over the bottom of a casserole dish and lay the fillets on top. Add another layer with the remainder of the pepper mix and then top with the cheese sauce.
For extra flavour, you can sprinkle some freshly grated parmesan over the top before browning off in the oven for another 5 minutes or so.
Serve nice and hot with some fresh green salad or baby potatoes for a tasty supper.