Cook pasta in salted water until al dente. Drain and rinse under cold water.

While pasta cooks, fry bacon in a skillet until crispy. Drain on paper towels and chop into pieces.

In a small bowl, whisk together mayonnaise, sour cream (or yogurt), lemon juice, salt, and pepper.

In a large bowl, combine cooled pasta, chopped bacon, and cherry tomatoes. Toss with half the dressing.

Just before serving, stir in chopped romaine lettuce and drizzle with remaining dressing. Toss gently to combine.