In a medium bowl, whisk together mayonnaise, apple cider vinegar, granulated sugar, salt, and black pepper until smooth and creamy.

Bring a large pot of salted water to a rolling boil. Add rotini pasta and cook until al dente, about 8-10 minutes. Drain and rinse under cold water.

Blanch broccoli florets in boiling water for 1 minute, then transfer to an ice water bath.

In a large mixing bowl, combine drained rotini, blanched broccoli, crispy bacon, chopped red onion, and shredded cheddar cheese. Stir in sunflower seeds.

Drizzle dressing over the pasta mixture and gently toss to coat evenly.

Cover and chill in the refrigerator for at least 30 minutes before serving.