Heat oil in a Dutch oven over medium heat. Add garlic and ginger; sauté 30 seconds or until fragrant. Add mushrooms; sauté 1 minute. Stir in broth, next 5 ingredients, and chili paste, if desired, and bring to a boil.
Stir in shrimp and snow peas, and cook 2 to 3 minutes or until shrimp turn pink. Add cornstarch mixture, and simmer 1 to 2 minutes or until slightly thickened. Remove from heat. Pour in egg, stirring slowly in one direction.
