A really good quiche!

1. Clean button mushrooms and trim the stalks flush with the cap.  Put them cap side down in a baking dish that's just big enough to hold them, and add some chicken stock, white wine, butter and a glug of light soy sauce.  Bake, covered, at a moderate temperature, until almost cooked; then remove the cover.
2. Meanwhile gently reduce finely chopped white onion and leeks in a frying pan with some butter.  To loosen it, add some of the juice from the mushrooms and continue cooking until the mixture is light brown and soft.  Then allow to cool
3. Allow the mushrooms to cook until the juices have reduced, evaporated, and the mushrooms have caramelised on their caps from the butter.  Remove from the oven and allow to cool.
4. Make a shortcrust case and blind bake.
5. Make the quiche filling with 3 eggs and a half pint of double cream, seasoned with salt.
6. Spread the onion and leek paste over the base of the pastry case, arrange the mushrooms, add grated cheddar.
7. Put it in the oven and use a jug to pour the egg mix in until it reaches the case's rim.
8. When the filling has started to set, add grated Parmesan and a good grinding of black pepper, then return to the oven until it rises like a souffle. 
9. Give it long enough to cool before eating that it becomes just warm to the touch, and the risen filling has collapsed back to set and solidify.

The idea here is to concentrate flavour into the mushrooms, and avoid any leakage of moisture from them into the quiche as it cools.