Heat 1 tablespoon oil in a large skillet over medium-high heat. Sauté onions and mushrooms for 3-4 minutes until softened.
Add bean sprouts and cook for another 2 minutes. Stir in chopped shrimp.
Mix soy sauce and cornstarch in a small bowl, then add to the vegetable mixture. Cook for 1 minute and remove from heat.
In a large bowl, combine beaten eggs with the cooked vegetable and shrimp mixture.
Heat remaining oil in the same skillet over medium heat. Pour egg mixture in ¼ cup portions to form pancakes.
Cook for 2-3 minutes until golden brown and set on bottom, then flip carefully and cook another 2 minutes.
Transfer to paper towels to drain briefly, then serve immediately topped with gravy and green onions.