Boil salted water in a 3 quart pot. Add the rotini pasta and cook according to package directions until al dente, meaning it is tender but still has a slight firm bite. This usually takes about 10 to 12 minutes.

Drain the noodles in a colander and rinse with cold water. I usually toss a few ice cubes directly into the colander to speed up the cooling process so the pasta is ready for the dressing.

In a large bowl, whisk the mayonnaise, sour cream, BBQ sauce, garlic, vinegar, salt, pepper, and cayenne until completely smooth.

Add the cooled pasta, green onions, and tomatoes to the bowl. Fold everything together gently so the pasta does not break.

Fold in the chopped iceberg lettuce. Hold the crumbled bacon separate and add it right before serving to keep the texture perfectly crispy.