Portobello Mushroom Tuna Melt

This was the first "Cooking Yourself Thin" recipe I ever tried and I think I made it just about everyday for a couple of weeks.   Being a lover of mushrooms, melted cheese, and summer tomatoes, this is a natural for me.  Two of these babies are just over 500 calories but I usually just eat one along with a couple of extra slices of tomatoes.  It's a perfect small meal or even a snack.

I found that I like to add balsamic vinegar to the tuna mixture for an extra depth of flavor.  If you're a mushroom lover, also, try this now while those wonderful summer tomatoes are available and add a thick slice on the top!

PORTOBELLO MUSHROOM TUNA MELT (serves 2)

4 Portobello mushrooms, stemmed, gills removed
2 Tbsp EVOO
1 (5 oz) can albacore tuna packed in water, drained and flaked
1 celery stalk, finely chopped
1/2 cup finely chopped fresh flat-leaf parsley
2 Tbsp fresh lemon juice
balsamic vinegar to taste, optional
S&P
4 thin slices Swiss cheese
4 slices tomatoes
1/2 cup mixed baby greens

Preheat the broiler.  Brush the mushrooms with 1 Tbsp oil.  Transfer to a rimmed baking sheet (lined with aluminum foil for easier clean-up) and broil, turning once until softened and cooked through, 6-10 minutes.

While the mushrooms are cooking, in a bowl, combine tuna, celery, parsley, lemon juice,  balsamic vinegar (if using), 1/2 tsp salt, 1/4 tsp pepper and remaining oil.

Remove the mushrooms from the oven.  Divide tuna mixture among mushrooms and spread evenly in caps.  Top each with a slice of cheese and broil until cheese melts and browns, about 2 minutes.  Top each mushroom with a tomato slice and 2 Tbsp greens.  Serve immediately.