Prepare the Ingredients: Ensure all your vegetables are sliced and shrimp is ready to cook.
Make the Sauce: In a small bowl, mix together the soy sauce, oyster sauce, and sesame oil. Set aside.
Cook the Shrimp: Heat the vegetable oil in a large skillet or wok over medium-high heat. Add the shrimp and season with salt and pepper. Cook for about 2-3 minutes, or until the shrimp turn pink and are just cooked through. Remove the shrimp from the skillet and set aside.
Stir-Fry the Vegetables: In the same skillet, add a touch more oil if needed, then add the sliced onion and garlic. Stir-fry for about 1 minute until fragrant. Add the bell peppers and continue to stir-fry for another 3-4 minutes, or until the peppers are tender-crisp.
Combine: Add the shrimp back to the skillet along with the sauce. Mix everything together until well coated.
Thicken the Sauce: Pour in the cornstarch mixture and stir until the sauce thickens, about 1-2 minutes.
Garnish and Serve: Remove from heat and garnish with sesame seeds and chopped green onions if you like. Serve hot over steamed rice or noodles.
