3 slices stale bread
2 tbsp. olive oil
1 tsp. thyme leaves
1/2 tsp. kosher salt
1/4 tsp. black pepper
8-10 large white mushrooms
3 tbsp. unsalted butter, divided
1 small yellow onion, finely chopped
1 shallot, finely chopped
4 cloves garlic, minced
1/2 tsp. dried oregano
4 oz. grated parmesan cheese
1/4 cup fresh Italian parsley, chopped
Directions
Preheat oven to 400 degrees.
Process bread in a food processor until it turns to coarse crumbs. Toss with oil, salt, pepper and thyme and spread over a baking sheet lined with parchment paper or aluminum foil. Bake until golden, approximately 6-8 minutes. Remove from oven and set aside.
Carefully remove the stems from the mushroom caps.
Finely chop the stems and innards.
On a different baking sheet lined with aluminum foil or parchment paper (or baking dish), place the cleaned mushrooms, stem-side down, on the sheet (or dish). Place mushrooms in the oven and bake until they start to release their juices, approximately 10 minutes.
While mushrooms are cooking, melt 2 tbsp. of the unsalted butter over medium-high heat in a medium skillet. Add the chopped mushroom stems and cook for five minutes, stirring occasionally. Add the remaining 1 tbsp. of butter, the onion, shallot, garlic and oregano, stirring occasionally until golden and cooked through. Season with salt and pepper, if necessary. Remove from heat and add to the bread crumbs in a large mixing bowl. Add parmesan and parsley and toss until well combined.
Pile stuffing into the opening of each mushroom, pressing gently, and lay on a clean baking sheet. Bake until the mushrooms are tender and stuffing is golden, approximately 15-20 minutes.