We've developed a nearly foolproof stir fry sauce that works well with virtually any combination of ingredients.
If the protein you're using is raw, sauté it first in a tablespoon or two of peanut or vegetable oil over medium-high heat until it's brown. Then add a tablespoon of ginger, a couple of chopped garlic cloves, some scallions if you like. If you're using cooked meat or tofu, toss it in now.
Last night we used some shamefully neglected broccoli from our CSA box, adding it about two minutes after the ginger, scallions, and garlic, then frying everything for about five minutes. Once the vegetables are nearly cooked, you can throw in greens. Spinach and chard are good; a few weeks ago we tried beet greens, and they were great.
Here's the liquid for the sauce. Many cookbooks would have you hold the sesame oil until the end because it's somewhat delicate, but you don't have to—in any case, it's nice to add a few drops to the finished dish for extra flavor.
1/2 cup broth (vegetable, chicken, or fish)
1 T. soy sauce
2 T. oyster sauce
1 T. toasted sesame oil (the brown stuff from the Asian section, not the light, health-food kind)
1 T. mirin (rice cooking wine) or sherry
Mix it all in a small bowl and add to the stir fry after the vegetables are nearly cooked.
Some cookbooks recommend dusting the meat in cornstarch or adding a tablespoon or two of cornstarch to the liquid mixture, but we like our sauces on the less gummy side, so we leave it out.
Serve with rice.