1/2 cup rice wine vinegar

2 tablespoons brown sugar

2 tablespoons reduced-sodium soy sauce

1 tablespoon cornstarch

1 tablespoon sesame oil

3/4 pound grass-fed beef tenderloin cut into 1-inch cubes

Salt and freshly ground black pepper

1 cup red bell pepper cut into 1-inch cubes (about 1 cup)

2 cups sliced bok choy, leaves and stems

Mix vinegar, sugar, soy sauce and cornstarch together in a small bowl and set aside. Heat oil in a wok or nonstick skillet over high heat. When oil is smoking, add beef and stir-fry 3 minutes, turning after one minute. Sprinkle beef with salt and pepper to taste. Add red bell pepper and bok choy. Let stir-fry 2 minutes, turning after one minute. Move the ingredients to the sides of the wok and add the sauce in the center. Bring all of the ingredients into sauce and stir-fry until the sauce thickens, 1 to 2 minutes. Serve over the rice.

Yield: 2 servings.

Per serving: 420 calories (38% from fat), 17.5 g fat (5.7 g saturated, 6.8 g monounsaturated), 84 mg cholesterol, 38.5 g protein, 24.1 g carbohydrates, 1.8 g fiber, 674 mg sodium.