Score five narrow grooves lengthwise along each carrot, Slice carrots into thin rounds to create flower–shaped discs.
Heat oil in a nonstick pan and cook onion over medium heat until transparent. Add carrots and stock. Cover pan and cook about 5 minutes; carrots should be crisp–tender. Remove pan from heat. Leave to cool. Cook pasta in plenty of lightly salted boiling water until al dente, about 4 minutes. Drain, rinse under cold running water. Leave to cool.
To make herb cream, whisk cream, yogurt, lemon juice and mustard in a large bowl until combined. Stir in herbs. Season with salt and pepper to taste.
Mix carrots and pasta into herb cream. Tear lettuce into large pieces and distribute among serving plates. Top with salad. Cut eggs into quarters and place on top.
Store eggs in the refrigerator because they will age more in a day at room temperature than in a week in a refrigerator. Store them in their carton so that you will be reminded of the use-by or best-before date.