1Preheat oven to 350 degrees.
Grease a 9x13 baking pan with the butter.
In large bowl mix together the bulk Italian sausages, egg, Italian bread crumbs, cilantro, mozzarella cheese, Worcestershire sauce, and pepper.
Place mushroom caps stem side up in a greased 9x13 pan.
Using a small mellon baller, scoop italian sausage mixture into the mellon baller. Now place the Italian sausage "meatball mixture" into each of the mushroom caps. Sprinkle with Romano cheese and mist with olive oil to moisten the top of the sausage "meatball".