Melt butter or margarine, add green onions, garlic and birdseye pepper and saute until tender. Add flour, stir and cook for 2 minutes until flour is blended; do not brown. Add water slowly, stirring all the while. Continue stirring and cooking until mixture comes to a boil. Add salt, pepper and parsley and cook 15 minutes or longer over low fire, stirring occasionally. Add more water if necessary to keep mixture the consistency of medium cream sauce. While mixture is cooking, boil cauliflower in salted water until tender but firm. Drain. Beat egg yolks and add vinegar. Stir into sauce; turn off fire immediately. Put cauliflower in bowl, pour sauce over it and serve immediately.