Thaw the Peas: Place the frozen peas in a colander and rinse under cool water until thawed.
Dry Thoroughly: Spread the peas on paper towels or a clean kitchen towel and pat completely dry. This step prevents watery dressing and helps the salad stay thick and creamy.
Prep Ingredients: Cook the bacon until very crisp, let it cool completely, then chop into crumbles. Finely dice the red onion and cube the cheddar into small, bite-size pieces.
Make the Dressing: In a small bowl, whisk together the mayonnaise, sour cream, apple cider vinegar, sugar, and black pepper until smooth.
Combine: In a large mixing bowl, add the dried peas, cheddar cubes, diced onion, and most of the bacon crumbles (save a little for topping).
Fold: Pour the dressing over the salad mixture and use a spatula to fold gently until everything is evenly coated. Avoid over-mixing so the peas stay intact.
Chill: Cover and refrigerate for at least 1 hour so the flavors meld and the dressing thickens slightly.
Serve: Stir gently, taste and add salt if needed, then garnish with the remaining bacon crumbles before serving chilled.