I made this burger after repeatedly having the kids leaving most of their burgers and parents left hungry after scoffing down their serve. This created one big burger where each person cuts off the amount that they want/can eat. No more wasted burgers. Works great at group gatherings too.
On a preheated BBQ add the burgers and onions, cook until the patties is browned then turn, add the mushroom and stir into the onions.
Half the roll and add evenly the lettuce, tomato, and red onion.
You can add the cheese onto the roll then place the patties on top, or put them on the patties while they are still on the BBQ for extra melting. Eventually the burger patties, cheese and cooked onion will be on the roll.
Close the roll and cut to preferred serving sizes.
Portion Size Tip
The recipe can be doubled and the roll upgraded to a french stick.