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

In a skillet over medium heat, fry the bacon strips for 6-8 minutes until crispy. Transfer to a paper towel-lined plate.

In a mixing bowl, combine mayonnaise or sour cream with a splash of milk until smooth. Season with salt and pepper.

In a large bowl, combine the cooled pasta, chopped bacon, and diced tomatoes. Pour the dressing over and mix until evenly coated.

Fold in chopped lettuce just before serving to maintain crispness.

Cover the salad and chill in the refrigerator for at least 15-20 minutes before serving.