2 cans flaked light tuna, drained
1/2 cup colored bell pepper, diced (I used yellow)
1/2 cup celery, diced
1/2 cup mustard leafs, finely chopped
1/2 cup mayo (I used Hellmann's)
1 teaspoon Old Bay seasonning
to taste Fresh groung black pepper
4 portobello heads, emptied
1 cup sharp cheddar cheese, shredded
1 tablespoon breadcrumbs