It’s not necessary to wash cultivated mushrooms before use as they are grown in sterile conditions and it is best avoided because the gills easily fill with water; just wipe the outer skin of the caps with a damp cloth. Mushrooms already contain a lot of moisture and this can come out during cooking, which is fine when you want them to be part of a stew or soup but not so good when you are after fried mushrooms.
For mushrooms on toast and in omelettes, tartlets and the like, choose small tightly closed mushrooms, slice them thickly and cook them over a high heat for a short period. Get the pan nice and hot, then put in a decent knob of butter and when sizzling, almost on the point of frothing and browning, tip in the mushrooms; don’t crowd the pan or they’ll stew. Let them brown first, then turn. If you constantly toss them the juices will run out. Seared like this so the moisture stays inside, you’ll bite into juicy mushrooms, bursting with flavour, with gorgeous crisp edges and a hint of browned nutty butter. Scrumptious! If you have a choice, pack loose mushrooms in a brown paper bag when buying them – it keeps them drier. Mushrooms don’t like to get sweaty and will rot quickly if kept in a damp bag. Mushrooms packed on trays lined with an absorbent pad store well for about a week. You can transfer loose mushrooms to a container lined with paper towels.
Photography Aaron McLean http://www.aaronmclean.com