Trim fat from beef. Cut in thin strips about 1"x2". Melt fat in pressure cooker. Add meat; cook over direct heat till browned, stirring frequently. Add onions, celery, garlic, seasonings, and bouillon cubes dissolved in hot water. Close cooker, bring to 15-pound pressure, and process for 3 minutes. Cool (letting pressure go down by itself). Add peppers, simmer for 5 minutes, add cornstarch blended with cold water. Cook till thickened. Add soy sauce. Serve with hot cooked rice or canned chow mein noodles.