Cooking with Parmesan - parmigiano reggiano to be more precise - generally involves grating the cheese into flakes or planing it into thin sheets. That mostly covers the traditional ground of adding it to dishes before they're cooked and garnishing them at the last minute. It doesn't cover one of the best ways to use it: eating it plain, pried off a wedge to form craggy little chunks and served at room temperature with a glass of wine. Some would drip a drop of long-aged balsamic vinegar onto it, but I like my Parmesan the way the dairy delivered it; it needs no enhancement.
Sometimes, especially if there are other snacks on the table, a few chunks remain uneaten. These leftovers usually get grated or snacked upon, but the other day I was looking at a small handful of the nuggets as I considered what to do with a quarter pound or so (115 g) of regular white mushrooms (uncooked), themselves left over from another dish. The rest of dinner was pretty well set, and one way or another the mushrooms would be a side dish. A tiny side dish once they'd cooked down.
The umami-upon-umami addition of leftover Parmesan to leftover mushrooms seemed a good way to make the dish so flavorful that its meager size would become irrelevant: every bite would pack a punch. It would have been a simple matter to sauté the mushrooms then grate the cheese over them, perhaps adding some fried breadcrumbs for crunch, but I got to wondering how the broken-up pieces of Parmesan would take to being cooked whole. After all, when I've simmered Parmesan rind in sauces (this adds lots of flavor - try it next time you make tomato sauce), the cheese has grown softer without collapsing; perhaps something similar would happen. Worth a try - whatever transpired, it would taste good.
So I quartered the mushrooms and cooked them in butter over gentle heat, seasoned with salt and pepper and a thinly sliced shallot, first to drive off excess water then to brown them slightly. I didn't cook them so long that they shriveled or dried out. When they were just about done, I added the Parmesan chunks and some thyme leaves, dropped the heat to low and stirred until the cheese was heated through and had stopped being crumbly, about two minutes.
The cheese behaved just as I thought it would: it was hot and moderately soft, but it retained its integrity - and lost not a whit of its flavor. The mushrooms - their own flavor concentrated by cooking - held up very well, and the ensemble was as intense as planned. A good little side dish.
Parmesan chunks used in this way have a lot of potential: with other vegetables (oil-braised greens, for instance) and even for certain soups. Imagine pasta e fagioli in which bean-sized pieces of Parmesan turn up unexpectedly in your spoon.