For the Beef Marinade:

• 12 ounces beef steak (ribeye, sirloin, or flank), cut into thin strips against the grain
• 2 tablespoons low-sodium soy sauce
• 1/4 teaspoon ground white pepper
• 1/2 teaspoon baking soda
• 2 teaspoons sesame oil
• 1/2 teaspoon sugar
• 1/2 teaspoon Chinese five-spice powder

For the Sweet and Sour Sauce:

• 3 tablespoons rice vinegar
• 1/3 cup packed brown sugar
• 1/3 cup ketchup
• 1 tablespoon tomato paste
• 2 tablespoons hoisin sauce (or oyster sauce)
• 1 teaspoon cornstarch
• 2 tablespoons low-sodium soy sauce

For the Stir-Fry:

• 2 large egg whites
• 1 cup cornstarch
• Vegetable oil, for frying
• 2 tablespoons peanut oil
• 3 cloves garlic, minced
• 1 medium onion, cut into 1-inch pieces
• 1 large bell pepper, cut into 1-inch pieces
• 1 red chili pepper, thinly sliced
• Cooked rice or noodles, for serving