Portobello Turkey Burger

Ingredients

• 2 lbs ground turkey breast
• 6 – 8 portobello mushrooms
• Freshly ground black pepper
• Sea salt
• Garlic powder
• Dried oregano
• 1 egg
• Olive oil
• 1 large red onion
• 2 tomatoes
• 6 cups arugula
• Raw cheddar cheese, sliced (optional)