Large portobello mushrooms are almost always on my weekly grocery list. A perfect stand-in for meat, they are really mature cremini mushrooms which can have caps from four to six inches wide. Their deep umami flavour (the fifth basic taste after salty, sweet, bitter and sour) is so robust that they don’t need as much salt. It’s a substantial vegetable – perfect for use in vegetarian dishes.
Select portobellos with firm, unblemished caps, then turn them over to check the gills (the dark brown feathery structure underneath). If they are dry, it means they’re fresh. If moist (or slimy) they’ve begun to spoil. Take them home and keep them in a paper bag before refrigerating. The bag will keep them dry up to 5 days.
Before cooking, cut off and discard the stem, which can be woody. Use a spoon to scrape off those gills because they can discolour other ingredients. Wipe the cap with a damp paper towel or just brush off any dirt. Cut in half, then thinly slice for stir–fries or keep whole if roasting or grilling.
A single portobello mushroom can contain more potassium than a banana, plus other nutrients such as vitamin C & D, iron and selenium. They are also low in fat, calories and carbs. They’re great stuffed or in fajitas and salads.