Preheat grill to 375 degrees F.

Prepare the patties:

• Into a large mixing bowl, crumble the vegan sausage and ground beef.
• Add steak seasoning blend, garlic powder, and Italian flat-leaf parsley.
• Using your very clean hands, mix and mash the ingredients until fully combined.
• Divide mixture into 6 even portions. Roll each portion into a ball, then use the palm of your hand to flatten each ball into a patty of about 1/2-inch thickness.
• Set the prepped patties aside, then make the pepper and mushroom topping.

For the topping:

• Into a medium skillet over medium heat, add the olive oil. When the oil is hot, add the red onions, cubanelle peppers, and mushrooms.
• Saute for 3-5 minutes, until vegetables are tender.
• Season with sea salt and ground black pepper, to taste.

Cook the burgers:

• Over your preheated grill, place the burger patties on direct heat.
• Grill for about 7 minutes per side, or until internal temperature reaches 160 degrees F.

Assemble the burgers:

• While burgers are still on the grill, add a spoonful of the pepper and mushroom mixture to each. Top each burger with a slice of provolone cheese then close the grill and allow the cheese to melt.
• Place your buns face side down on the direct heat of your grill and toast for 1-2 minutes.
• Place cooked burgers on the toasted buns and add any additional toppings.
• Serve warm.