1. Bring 6 cups water to a boil in a large saucepan. Add carrots; reduce heat, and simmer 5 minutes or until crisp-tender. Drain; rinse under cold water. Rub carrot peels off with a clean, dry kitchen towel.
2. Melt butter in a large skillet over medium-high heat; swirl to coat. Add onion; sauté 3 minutes or until slightly tender. Add carrots, sugar, vinegar, salt, and pepper; cook 2 minutes or until sugar dissolves and carrots are thoroughly heated. Stir in tarragon. Top with pea tendrils.