* Oyster sauce is an ingredient used frequently in Oriental Cooking. You'll find it in either your grocery or an Oriental food store. - Partially freeze lamb. Thinly slice into bite-size strips. In a 2-cup measure stir together 1/3 cup water, oyster sauce, cornstarch, grated gingerroot, and chicken bouillon granules. Micro-cook, uncovered, on 100% of power for 1 1/2 to 2 minutes or till thickened and bubbly, stirring every 30 seconds. Set aside. I a small nonmetal bowl combine bok choy, sliced mushrooms, and 2 T water. Cover with vented clear plastic wrap. Micro-cook, covered, on 100% power 3 to 4 minutes or till bok choy is just crisp-tender. Drain. Cover and set aside. Preheat a 6 1/2-inch microwave browning dish on 100% power for 3 minutes. Add cooking oil to browning dish. Swirl to coat dish. Add lamb strips. Micro-cook, covered, on 100% power for 1 1/2 to 2 1/2 minutes or till lamb is done. Drain off fat. Stir in oyster sauce mixture with toasted pine nuts and bok choy mixture. Serve over hot cooked rice if desired.