handful button mushrooms, thinly sliced
1 onion, thinly sliced
1 red pepper, cut into 1cm/陆in strips
1 green pepper, cut into 1cm/陆in strips
40驳/1陆辞锄 plain flour
paprika, chilli powder, garlic granules, or herb mix, to taste
2 tbsp vegetable oil
40驳/1陆辞锄 unsalted butter
150g/5陆oz mature cheddar, grated
2 slices Monterey Jack cheese
2 slices American cheese or burger cheese
500ml/18fl oz semi-skimmed milk
75驳/2戮辞锄 mozzarella, grated
75驳/2戮辞锄 Parmesan, grated
1 rib-eye steak (about 450g/1lb), frozen and partially thawed so it is just sliceable
2 x 30cm/12in sub rolls or hoagie-style rolls