Step 1

Using a large skillet, add the olive oil and place over medium heat. Once hot, add remaining ingredients (onions, bell pepper, mushrooms, barbecue sauce, garlic, pepper and salt). Cook for 12-15 minutes, stirring occasionally, or until soft. Remove from heat and set aside.

Step 2

Preheat grill to medium-high heat.

Step 3

In a large bowl, combined all of the burger ingredients (except for buns and sliced pepperjack cheese) until just combined. Shape into 4 patties and gently indent the center of each patty with your thumb.

Step 4

Brush grill grates with vegetable oil or spray with nonstick grilling spray. Grill burgers for 4-5 minutes per side, or until they reach desired doneness.

Step 5

{Optional} Place burger buns cut-side down on grill for 1-2 minutes.

Step 6

Assemble burgers and top with sautéed onions, peppers and mushrooms. Finish by adding a slice of pepperjack cheese on top.