Rinse the mushrooms lightly to clean them of any dirt, but don’t use too much water. You don’t want them to get soggy.
Carefully break off the mushroom stems (they should come off easily, or you can cut them). Set them aside and toss them into a vegetable or noodle stir-fry, vegetable stock, or an omelette! You might think about including them in the stuffing, but that will make it too wet! A drier stuffing is key to making these stuffed mushroom caps a success. Pat the mushroom caps dry with a paper towel, and arrange them neatly on a sheet pan with the cap side up.
Brush the mushroom caps with melted butter, turning them over afterwards so they are top-side down.
Preheat the oven to 375°F/190°C. While the oven is preheating, make the stuffing. To the remaining butter, stir in the onion powder, garlic powder, thyme, paprika, and salt. Use a rubber spatula to mix in the dried breadcrumbs until all the breadcrumbs are saturated with butter. Stir in the the parmesan cheese and parsley.
Stuff a spoonful of breadcrumb mixture into each mushroom cap, but don't pack or compress the stuffing. Bake for 9-12 minutes. The mushrooms should be cooked through, but firm enough to pick up with your hands. Serve immediately!
Notes
(Makes 6 servings, about 3-4 mushrooms per person)