Boil water in a large pot and add all the pasta. Let cook for 12 minutes (you want it to be SOFT not AL DENTE). Drain well and mix with a little mayonnaise to prevent sticking.
Finely dice/mince or shred your onion and rinse with cold water to remove bitterness. Shred your carrots and add the carrots, onion, mayonnaise, and pepper to cooled pasta. Mix and chill for at least 1 hour before serving.