Boil a large pot of salted water over high heat. Add the rotini pasta and cook until al dente, about 8 to 10 minutes. Drain and rinse under cold water to stop cooking.

Chop the broccoli into small florets and finely dice the red onion. Set aside in a mixing bowl.

Whisk together mayonnaise, sugar, white vinegar, salt, and pepper in a medium bowl until smooth.

In a large mixing bowl, combine the drained pasta, chopped broccoli, bacon, shredded cheddar, diced onion, dried cranberries, and walnuts. Toss gently.

Pour the dressing over the pasta mixture and toss to coat gently. Do not overmix.

Cover and refrigerate for at least 1 hour before serving. Stir gently before serving.