Fresh mushrooms, rinsed, dried, and sliced. (I used about 4-5 medium shiitake per person, for this dish, or a couple of handfuls)
Note: While most mushroom stems are edible, if you use shiitake, as I did here, you must remove and discard the entire stem.
1 to 2 medium garlic cloves, per person, peeled and minced
Fresh parmesan cheese (Fontina or milder fresh mozzarella also work well)
A little butter
Fresh thyme for garnish (optional)
Heat a cast iron or other heavy skillet over medium heat. Drizzle pan generously with olive oil, and add a tablespoon of butter per batch of mushrooms.
The key to perfect pan roasted mushrooms is this simple technique: Cook mushrooms in batches in a single layer, without stirring, to let each side quickly brown. It only takes a couple of minutes per batch (and one batch is enough for about 3 people, in a medium sized pan).
Also, hold off on adding the garlic until the last couple of minutes so it won't burn, and don't season the mushrooms until after they cooked, otherwise the salt will release moisture in the pan during the cooking process, and they will be less crispy. (Not a catastrophe, of course, but just not quite as good.)
When you flip the mushrooms to cook the other side, (using tongues is the quickest method), stir the garlic around as well, so it doesn't burn.
Meanwhile, slice your bread (either thick or thin, depending on your preference), drizzle with olive oil, season with salt and pepper, and toast for just two minutes or so under the broiler on a sheet pan, until lightly golden-brown.
Top the toasts with the roasted mushrooms and a sprinkle of fresh thyme, if you wish.
You can serve the toasts this way, or take it one step further and add a sliver of fresh parmesan cheese, or a bit of grated fontina or fresh mozzarella.
If you add cheese—a nice way to pack a little more protein in the meal, if this is lunch or brunch—slide the toasts back under broiler for just another minute until the cheese is melted.
Serve and enjoy hot or room temperature. I find the toasts without cheese taste better room temperature, while the cheese version is best if eaten immediately.