This is a slightly unusual way of preserving mushrooms, but it works better than drying for many aromatic species . . .
500g Chanterelles, hedgehogs or fairy rings
3 Cloves garlic
1 Small onion
Roughly chop the onion, garlic and mushrooms and sauté in about half the butter for 5 – 10 minutes then pulverise in a food processor for a few seconds. Transfer into a clean kilner jar, pressing down to exclude any air bubbles. Meanwhile melt the rest of the butter in a pan, skimming off any scum to clarify, then pour over the top of the mushroom and butter mix. Place in a warm oven for half an hour and then seal the lid. This will keep for several weeks in the fridge. Use a spoonful at a time to flavour quiches and casseroles.