Start by thawing 2 cups of frozen peas under cool running water for 3–5 minutes; drain well and set aside.

In a large mixing bowl, combine the thawed peas with 1 cup of diced cheddar cheese, 1 cup of chopped celery, 1 cup of chopped red bell pepper, and ½ cup of finely chopped red onion. Gently fold the ingredients together with a spatula.

In a separate bowl, whisk together ½ cup of mayonnaise, ½ cup of sour cream, 2 tablespoons of apple cider vinegar, and 1 tablespoon of sugar until creamy. Season with salt and pepper.

Pour the dressing over the pea salad mixture and gently toss everything together, ensuring each ingredient is coated.

Cover the bowl tightly and refrigerate for at least 1 hour to allow flavors to meld.

Before serving, give the salad a gentle stir and transfer to a serving dish.