The BEST Stuffed Bell Peppers with Ground Beef

Ingredients

• 1 pound lean ground beef 90% lean
• 4 mushrooms chopped
• 3 ears of fresh corn kernals or 1 1/2 cups frozen corn
• 2 ribs of celery chopped thinly
• 1 medium onion chopped
• 2 cloves garlic minced
• 2 14.5 ounce cans petite diced tomatoes with juice
• 2 tablespoons concentrated tomato paste
• 2 tablespoons basil
• 1 tablespoon oregano
• 1/2 teaspoon red pepper flakes
• kosher salt and freshly ground black pepper to taste
• 1 1/2 cups cooked long grain rice
• 1/4 cup chopped Italian parsley
• 6 bell peppers
• 1 cup shredded fontina cheese or monterey jack cheese