Mushroom Stroganoff - and thieving fridge fairies

Well, this started off as mushroom stroganoff. As reflected in the picture, it is renamed "Minimilist Mushroom Stroganoff". Why? Ah you see, I KNOW I had another punnet of mushrooms in the fridge, absolutely certain of it. However, when the other food was simmering away and the time came to USE that punnet...oh no...the dreaded fridge fairies had come thieving again. They are neighbours to the evil washing machine gnomes that love stealing one half of any pair! So you will get the intended recipe and the recipe pictured. Anyone have ideas for trapping fridge fairies?
As I am writing, I am drinking my favourite juice combo - 3 apples, half a lemon, one small fennel bulb - juice together - YUM!!

                                      Minimilist Stroganoff
Feeds 2
6 baby leeks or 2-3 large, washed and sliced
1 clove garlic, chopped
30ml butter
1/2 punnet mushrooms
2T brandy
1t wholegrain or other mustard
salt and pepper
1t tomato paste
200ml cream

Fry leeks and garlic gently in butter (or olive oil, but butter tastes better), add mushrooms and fry till cooked and dry. Add brandy, cook off rapidly, add mustard, salt and pepper. Add cream and simmer slowly for 5 min. Voila!! Good with mashed potatoes or rice. Some parsley stirred into the mash is nice.

NORMAL Stroganoff: replace leeks with one onion or just 2 leeks, use a WHOLE punnet of mushrooms and continue. You can use any mushrooms, but brown or portobellini work best