Thaw shrimp or scallops, if frozen
If using shrimp, peel and devien, leaving tails intact (optional)
If using scallops, cut any large scallops in half.
Rinse shrimp or scallops; pat dry with paper towels. Set aside.
In a small bowl combine water, soy sauce, vinegar, cornstarch, and sugar; set aside.
In a wok or 12-inch skillet, cook and stir garlic in hot oil over medium-high heat for 15 seconds, (Add more oil as necessary during cooking.)
Add broccoli, carrot, and onion.
Cook and stir for 3 minutes.
Add mushrooms; cook and stir for 1-2 minutes more or until vegetables are crisp-tender.
Remove vegetables from wok with slotted spoon.
Stir soy sauce mixture.
Add to wok;, cook and stir until slightly thickened and bubbly.
Add shrimp or scallops; cook about 3 minutes or until shrimp or scallops are opaque.
Stir in vegetables; heat through.
Serve with rice and sprinkle with cashews.
You can substitute shrimp or scallops with chicken or beef, and use as many or few vegetables as you like.
This dish can also be served over vermicelli, angel hair, or thin spaghetti pasta, or Asian noodles.