There is no end to what might be used to stuff a mushroom. These are simple: onions, garlic, cheese, mushroom stems, and seasonings. No bread crumbs are used, making them great for low-carb or gluten-free diets.
They are delicious as a side dish and also as appetizers. They can be frozen and reheated, making them great for doing ahead. Since everything is cooked before assembling, they can sit in the fridge for a day before baking, if you don't want to freeze them.
The recipe is very forgiving on amounts; use your judgement.
12 medium-sized white mushrooms, cleaned
1 small white onion, finely minced
1-2 cloves garlic, finely minced
1 cup finely shredded cheese - I like Swiss or Gouda
1 teaspoon fresh thyme leaves (or 1/2 tsp dried)
1 teaspoon minced parsley
salt and pepper to taste
1. Remove the stems from the mushroom caps. Reserve. Lightly oil the tops of the caps. Place top-side down in a baking dish and bake at 350 degrees for 10-15 minutes. Remove from oven and let cool.
2. Meanwhile, mince the mushroom stems. Heat 1 Tablespoon olive oil in a skillet and saute the mushroom stems, onion and garlic until tender and fragrant, about 5-10 minutes. Turn up the heat towards the end to brown a little.
3. The mushroom caps will have collected some water in them as they cool. Gently pour the mushroom liquid into the onion mixture and stir. Add thyme, salt and pepper. Let cool.
4. Add the finely grated cheese to the cooled onion mixture. Fill the caps. Press the mixture in. There may be some stuffing remaining.
5. Bake at 350 degrees for 10 minutes or until hot. Serve immediately or freeze for later.