A stir-fry is only as good as its ingredients. Use fresh vegetables, preferably ones with contrasting colors, flavors and textures. If pressed for time, you may use packages of pre-sliced vegetables and meat.
Pick a protein
Choose a lean, tender cut, such as:
■ Boneless, skinless chicken breasts or tenders.
■ Pork tenderloin or center-cut loin.
■ Steak, such as flank or boneless sirloin.
■ Thick, firm white-fleshed fish, such as catfish, halibut or sea bass, and shellfish, such as shrimp or sea scallops.
■ Firm or extra-firm tofu.
Chopping and slicing
All the ingredients — meat, seafood, vegetables — should be sliced thinly and uniformly to ensure that everything cooks quickly and evenly.
■ Bell peppers: Cut into thin strips.
■ Bok choy, asparagus, green beans, scallion greens: Cut into 11/2-inch pieces.
■ Broccoli, cauliflower: Cut into small florets.
■ Carrots, sweet potatoes: Cut into 1/4-inch-thick slices.
■ Meat, fish: Cut across the grain into strips 1/4 inch thick and 2 inches long.
■ Seafood (shrimp, scallops): Leave whole.
■ Snow peas, sugar snap peas: Leave whole, with ends trimmed.
Make a sauce
Prepare the sauce in the same pan you'll be using to stir-fry the protein and vegetables. Heat the seasonings, such as garlic and ginger, to bring out their fragrance and flavor. Then add the remaining ingredients and cook until sauce thickens to the consistency of heavy cream. You can prepare sauces in advance, or make a double batch and refrigerate half for another time. (But don't double the cornstarch — that will make the sauce too thick. Instead, use 11/2 times the specified amount.)
Cook the vegetables
Because some vegetables take longer than others, add them to the pan in stages, beginning with those that require the most time.
■ Green beans: 9 minutes.
■ Cauliflower: 8 minutes.
■ Sweet potatoes: 8 minutes.
■ Asparagus: 4 minutes.
■ Carrots: 4 minutes.
■ Bok choy: 2-3 minutes.
■ Broccoli: 2-3 minutes.
■ Snow and sugar snap peas: 1 minute.
Source: Real Simple