Italian

1 tablespoon olive oil
2 cups frozen Southern-style hash brown potatoes
8 ounces Italian sausage, cooked, sliced
1 cup sliced mushrooms (optional)
1 cup frozen tri-color pepper mixture
4 eggs
1/4 cup milk or water
1/4 teaspoon salt
1/4 teaspoon dried oregano leaves
1/2 cup shredded Italian cheese blend