Bring a large pot of salted water to a vigorous boil over high heat. Add the rotini pasta and cook according to package instructions until al dente, about 8–10 minutes. Drain in a colander and rinse under cold water to cool.

Chop the broccoli into small, bite-sized florets and finely dice the red onion. Set both aside for later use.

In a separate mixing bowl, combine the mayonnaise, sugar, white vinegar, salt, and pepper. Whisk until smooth.

Transfer the cooled pasta to a large mixing bowl. Pour the dressing over the pasta and stir gently until well-coated.

Add the chopped broccoli, bacon, cheddar cheese, red onion, cranberries, and walnuts. Toss gently to mix until evenly distributed.

Cover the bowl and refrigerate for at least 1 hour before serving to allow the flavors to meld.