Finely chop mushrooms or gently pulse in food processor.
In skillet, heat oil to medium-high heat. Add mushrooms and black pepper, sautéing 5 to 7 minutes, or until golden brown. Remove from heat and let cool for 5 minutes.
Transfer cooled mushrooms to medium bowl. Add ground beef, Italian seasoning and salt, mixing until combined.
Make 5 patties. Grill burgers 8 to 12 minutes or until temperature reads 160°F with instant read thermometer. Place burger on bun. Add suggested toppings, if desired.
Jarred roasted red bell peppers
Sliced red onion
314 calories | 13g fat, 4g saturated fat, 25g carbs, 24g protein, 4g dietary fiber, 503mg sodium, 59mg cholesterol