Servings: 12
Ingredients : 

2 large eggs
2 cups finely chopped mushrooms
2 teaspoons ground black pepper
1 teaspoon garlic salt
2 small onions, finely chopped
salt to taste
12 medium (blank)s portobello mushrooms, or more to
taste
2 pounds lean ground beef, or more to taste
2 green bell pepper, halved and seeded
2 red bell pepper, halved and seeded
2 yellow bell pepper, halved and seeded

Directions  : 

step 1 Preset the outdoor bar-b-que grill for medium-high heat and gently oil the grate.

Step 2 Mix surface beef, egg, red onion, and chopped mushrooms together in a bowl, seasoning with pepper, garlic sodium, and salt as you mix. Type mixture into patties about 2 in . in diameter.

Step 3 Grill patties on the preheated grill until browned and desired doneness is reached, 5 to 7 minutes per side. An instant-read thermometer placed into the middle should read at least 160 levels F (70 levels C).

Step 4 Grill portobello mushrooms, green bell pepper, red bell pepper, and yellow bell pepper on the grill until sensitive, 3-5 minutes per side. Use 2 mushrooms so that as the ‘bun’ for the hamburgers.