Why not? You see enough of them in restaurants for $10 or more!
We minced sweet onions, mushrooms and yes, even carrot.
The original recipe calls for roasted garlic too - that sounds fantastic, but we didn't get that far. Although, the first time we made these I did add crushed garlic, and that was a nice touch.
Toasted up wheat buns on the grill.
Add some fresh cut cheddar to melt, add your favorite toppings...YUM
This is the way to have a burger. Just a little extra work, but worth it.