Generously-sized portobello mushrooms are wonderfully meaty, and they add a boost of umami to everything from burgers to pasta. But many of us don't realise the proper way to prep and clean them before cooking.
If you think prepping a portobello is as basic as running it under water before plopping it on the stove, think again. This America's Test Kitchen video, which includes what parts of the mushroom to remove before cooking, how to spot a fresh portobello from an old one, and the best way to clean dirt off portobellos, is a helpful place to start.
Another useful primer is this mushroom video starring J. Kenji López-Alt from the Serious Eats archives. In it, he points out the best methods for removing the stem and the gills (yep, those gills need to go), as well as why and how to score the tops of the mushrooms lightly when cooking them whole.
Learn to Cook: How to Properly Prepare Portobello Mushrooms [America's Test Kitchen]
Knife Skills: How to Properly Prepare Portabella Mushrooms [Serious Eats]