Instructions
Preheat oven to 425 degrees F.
Place mushrooms on a baking sheet smooth side down. Brush evenly with oil. Bake for 20-22 minutes, turning after 10 minutes. Mushrooms will be softened. Set aside.
While mushrooms are baking, combine tuna, avocado, lemon juice, mustard, parsley, and garlic powder in a medium bowl; mix well.
Top each mushrooms evenly with tuna mixture, tomato and cheese.
Return mushrooms to oven. Bake for 3-5 minutes, or until cheese is melted. Serve immediately.
*Green, Blue, 1/2 Red Container