1 pound large mushrooms
4 tablespoons butter plus a little for greasing baking dish
4 green onions, with much of the green, trimmed
1/2 cup finely minced ham
1 small clove garlic, finely minced
2 cups coarsely chopped baby spinach
1 cup fresh bread crumbs
1/4 teaspoon salt
1/4 teaspoon pepper
1/4 to 1/2 cup Mozzarella cheese

Wash and trim the end of stems from mushrooms. Pop remaining stem out. Chop stems and set aside. Melt 2 tablespoons butter; brush over mushrooms. Spray a shallow baking dish (about 8-inch square, or one which will fit mushrooms in one layer) with butter-flavored spray or grease with butter.
Heat remaining 2 tablespoons of butter in a skillet. Chop green onions; combine with reserved chopped mushroom stems, ham and garlic. Add to skillet along with the spinach; sauté until tender. Add bread crumbs, salt, and pepper to vegetable mixture; stir well. Add a little cream to moisten more if necessary. Fill each mushroom cap with a little of the stuffing, mounding up. Sprinkle with Mozzarella cheese. Bake at 350° for about 20 minutes, until cheese is melted and mushroom caps are tender.

Makes about 16 to 20 stuffed mushroom appetizers.

These would also be very good with crumbled cooked bacon, about 1/4 cup, if you don't have or care for the ham.