How to barbeque the best mushroom cheeseburger?

I like to fill the burgers. I grill the mushrooms with garlic, olive oil, parsley, a tad bit of honey mustard, and chopped onion ahead of time and pop it in the fridge.

Then I mix ground chuck with, coco powder (browns the meat and adds a great taste, trust me) soy sauce, garlic butter, and season all.

Then I take the meat and flatten out thin pattys. On top of one thin patty I put cubed pepper jack cheese and my premaid mushroom onion mix. Then I fold over another thin patty on top. I seal the sides together with my hands.

My husband calls them hidden burgers. Bc he never knows what’s inside. I make a lot of stuffed burgers all year. On the grill, in the oven, and on the stove top. =o)

I’m with you on the portobello - great on a burger.

Here’s my version of the mushroom cheeseburger:

-hickory smoked all-beef patty (mix the patty with the liquid smoke, garlic, onions,salt and pepper) -portobello marinated in balsamic vinegar and grilled until tender -top the patty with provolone and let melt -on the bun: basil-mayo sauce -topped with green peppers and the grilled mushroom

requires no mustard, lol