This mixture may make more than you need, as the size of field mushrooms varies such a lot, and also you can fill the mushrooms to varying degrees, but if you do have leftover mixture, there are plenty of ways you can use it, aside from whipping out another one or two mushrooms.You could use it as a filling in sandwiches or wraps, put it on little squares of puff pastry with some tomato or use it in something like an eggplant bake. The cashew mix will keep in the fridge for about 2-3 days.