Wash broccoli thoroughly; cut into flowerettes, discarding tough ends and lower stalks. Arrange broccoli in a steaming rack. Place over boiling water; cover and steam 10 minutes or to desired degree of doneness. Plunge immediately into ice water. Drain thoroughly. Transfer broccoli to a serving dish; cover and chill.
Combine oil, vinegar, mustard, and salt in a small jar; shake vigorously. Spoon dressing over broccoli; toss lightly.
Place red pepper rings on lettuce leaves, and spoon broccoli into rings. Garnish with grated egg yolk, and serve immediately.