Bring a large pot of salted water to a boil. Add the pasta and cook until al dente, about 8-10 minutes. Drain and rinse under cold water, then transfer to a large mixing bowl.

Preheat the oven to 400°F (200°C). Line a sheet pan with parchment paper, arrange the bacon, and bake for about 25 minutes until crispy. Cool and chop into pieces.

In a mixing bowl, combine sour cream and ranch dressing, whisk until smooth and creamy.

Add the cooled pasta, green onions, cheddar cheese, and half the bacon to the dressing. Stir gently to combine.

Pour the dressing over the pasta mixture and toss until well coated. Cover and refrigerate for at least 30 minutes.

Before serving, stir the salad and sprinkle with remaining bacon. Add garnishes if desired, and serve chilled or at room temperature.