Partially freeze the steak for easier handling, then slice it diagonally across the grain into 1/4-inch strips; set aside.
Next, in a large bowl combine 2/3 cup water, onion, soy sauce, bouillon, Worcestershire sauce, garlic, salt, and pepper, stirring well. Add the steak, mixing again to coat evenly, then cover the bowl, and refrigerate it for one hour.
Drain the steak, reserving the marinade, and set the steak aside.
Blanch the carrots and cauliflower in boiling water for 3 minutes. Drain and set aside.
To stir-fry, coat a large skillet or wok with cooking spray, then heat it on medium-high for 2 minutes. Add the steak and the stir-fry for 3 minutes. Add the mushrooms and then stir-fry with the steak for 1 minute. Add the pea pods, carrots, and cauliflower and stir-fry for 2 minutes, or until the vegetables are tender and crisp.
Combine the reserved marinade, 1/4 cup water, and cornstarch, stirring to blend well. Pour over the steak mixture and then continue to stir-fry until the mix has become thickened and bubbly.