I listed it as lunch or dinner, because with a little variation it can be a real good dinner or makes a great lunch sammie.
The ones in these pics happens to be chopped beef because that's what I had on hand.
Here's a couple of examples.
Start with large Portebello mushrooms. At this point you can decide whether to marinade them or not depending on what you are going to cook with them. The ones here are not marinaded, they are rubbed with Safflower oil on the outsides.
In the small pot is melted garlic butter, Balsamic vinegar, lemon juice, and a little Worcestershire sauce. Some of this will be poured into the shrooms while they are grilling and some will be brushed on the rolls when grilled. I use a griddle to heat up the meat, onions, bacon, or anything else going on the shrooms.
Now that the shrooms are almost done, I add the meat to the inside of them. This is where I go in different directions depending on whether it's a sammie or a dinner.
If it is going to be a sammie, I put on the rolls to grill and add sliced cheese to the top of the stuffed shroom. These have Munster & Pepper Jack, but use what you like.
Stuffed shroom sammie with some hot mustard. Get creative, use different cheeses and add onions, maters, bacon, or anything else you like.
If I'm going to do a dinner, I change a few things.
I put crumpled cheese on the stuffed shrooms. One has Blue cheese and the other has Feta in the picture.
Stuffed shrooms with garlic mashed taters and a garlic-horseraddish cream sauce and a marinated Artichoke heart and olive salad.
These are a quick and easy way to cook up something different from leftovers. Be creative with the meats, marinades, sauces, and cheeses for a wide varity of flavors. Another great variation on this is to use tomatoes instead of shrooms. They grill up real good too.
Edit - I haven't tried it yet but, I would bet some pizza sauce and Mozzarella cheese would be real good.
Just had dinner and I am hungry again! 
