Italian-Style Stuffed Mushroom Appetizers

Preheat the oven to 400 degrees F.

Carefully remove the mushroom stems. Coarsely chop the stems and set aside the mushroom caps.

Add the butter to a large skillet over medium-high heat. When melted, add the mushrooms stems and onions. Cook, stirring frequently, for 5 minutes or until the vegetables are tender.

Add the garlic to the skillet and cook, stirring frequently, for about 1 minute or until the garlic is fragrant.

Place the bread crumbs in a bowl. Stir in the vegetables and butter from the skillet. Add the mozzarella, parmesan, parsley, vinegar, salt, and black pepper. Mix well.

Place the mushroom caps stem-side up on a rimmed baking sheet. Fill each cap with some of the breadcrumb filling, mounding the filling slightly (do not pack the filling).

Place the baking sheet in the oven and bake at 400 degrees F for 25 minutes or until the mushrooms are tender and the filling is golden brown.

Serve hot.