Lynn's Recipes - Broccoli and Cheese Egg Casserole

Ingredients

• ½ cup red onion, finely chopped
• 1 cup mushrooms, finely diced
• 1-1/2 cups broccoli, finely chopped
• 1 can diced tomatoes, drained (14-1/2 ounce)
• 12 eggs
• ½ teaspoon salt
• ½ teaspoon black pepper
• 2 cups sharp shredded cheddar cheese