Begin by bringing a large pot of salted water to a boil over high heat. Add the ditalini pasta and cook according to package directions, usually around 8-10 minutes, until al dente. Drain the pasta and rinse it under cold water.

In a skillet over medium heat, cook the bacon until crispy, about 6-8 minutes. Remove from skillet and place on a paper towel-lined plate to drain. Cool and chop into bite-sized pieces.

In a large mixing bowl, combine the cooled pasta, sweet corn, chopped bacon, sharp cheddar cheese, diced jalapeño, and sliced spring onions. Toss to mix evenly.

In a separate bowl, whisk together the mayo, sour cream, buttermilk, and dry ranch dressing mix until smooth. Add parsley, lemon juice, salt, and pepper; mix well.

Pour the dressing over the pasta mixture. Gently toss to coat everything evenly in the dressing.

Cover the bowl with plastic wrap or transfer to an airtight container. Chill for at least 1 hour to meld flavors.

Before serving, stir the pasta salad and garnish with additional chopped parsley if desired. Serve cold.