Instructions

  1. Line a rimmed baking sheet with aluminum foil; preheat oven to 350 degrees.
  2. In large skillet, melt butter over medium heat.
  3. Add onion and garlic; cook for 4-5 minutes, or until onion is tender.
  4. Remove from heat.
  5. Stir in pepperoni, Canadian bacon, cheeses, tomato paste and Italian seasoning.
  6. Spoon mixture evenly into mushrooms caps.
  7. Place mushrooms on prepared baking sheet.
  8. Bake for 20 minutes.
  9. Serve immediately.