1 portobello mushroom, gills scraped
1 kaiser-style bun with caramelized onions baked on top, split
Olive oil for glazing
1 ounce Dubliner cheese (about 1 slice)
Grill mushroom until cooked through. In sauté pan, briefly cook mushroom in oil to glaze.
Place slice of cheese on mushroom cap and place under broiler to melt cheese.
Serve on bun.