It's even low carb... ;-)

No source, I like to make stuff up as I go along so this is my own
recipe.

Stuffed Portabello caps:

9 medium portabello mushrooms

2 stalks celery (optional)
1 oz. fresh basil leaves
1/4 oz. fresh thyme
2 small roma tomatoes
1 cup shredded jack cheese (or cheese of choice)
1 lb. lean ground beef (I used 96/4)
1 tbs. grated fresh Ginger root
1 medium shallot
1 pinch black pepper
2 tbs. toasted sesame seeds
4 oz. baby spinach leaves
1/4 cup EV Olive Oil

Remove stems from the caps, remove dirty end then chop the stems and put
them into a bowl. Take the caps and oil the outside with additional
Olive or Grapeseed oil and place on to plates.

Chop all other ingredients and add to chopped portabello stems.

Mix well and stuff into oiled caps.

Grill on Electric grill for 10 minutes.

Serve with a light spray of Soy Sauce and salt to taste.

Cheers! :-)