Pieczarki Nadziewane (Stuffed Mushrooms)

Directions

Preheat oven to 400℉ (200℃).

Grease 9 to 10 inch sqaure baking dish .

Seperate mushroom caps and stems; set caps aside.

Finely chop stem pieces.

Melt butter over medium heat.

Add onion; sauté until soft, about 3 minutes.

In bowl, combine sautéed onion, chopped mushroom stems, bread crumbs, sour cream and hard-cooked egg.

In a bowl, beat egg with fork. Add to onion mixture. Stir in parsley, salt and pepper until blended. Pack about 1 rounded teaspoon stuffing mixture into each reserved mushroom cap. Arrange, stuffing-side up, in greased dish. Place 1 cheese square on each cap. Bake, uncovered, 20 to 25 minutes.