Filled mushrooms are an adventurous way to use up leftover vegetables. Any vegetables will do, and depending of course on how many mushrooms you are planning to fill, not a lot of them either.
Leftover cooked vegetables
Vegetarian cheese suitable for thin slicing. I tend to use cheddar or emmenthal
If the leftovers are already mashed - potatoes, say, or parsnips or swede - leave as they are. Vegetables originally cooked in chunks - carrots, say, or turnips, roast potatoes, cauliflower - should be cut into smaller pieces. Onions and leeks should be similarly chopped up. Gravy or sauce (though not too much) can be added. So can vegetarian mince.
Mix the vegetables of your choice together in a bowl. Moisten slightly, with stock or leftover sauce or gravy, but be careful not to make the mixture too wet.
De-stalk the mushrooms and brush them thoroughly inside and out with oil. Place skin down in a greased or oiled oven dish.
Place a couple of thin slices of cheese in the base of the mushrooms and fill with the vegetable mixture. Then place three or four more thin slices of cheese across the top of the mixture, carefully overlapping them. Smooth neatly into place, brush with oil and pour a small amount of water into the base of the dish to keep the mushrooms moist. Cook in a pre-heated oven Gas 6 (400°, 200F◦) for 20 minutes.
Eat the cheese-topped mushrooms by themselves as a snack with chutney or pickles or a sauce. Or as part of larger meal accompanied by potatoes, fresh vegetables, rice, chips or pasta.