Pat the thawed peas dry with paper towels to remove excess moisture—this keeps the dressing from becoming watery and diluted. Cook the bacon until very crispy, then crumble it into bite-sized pieces. Finely dice the red onion into uniform 1/4-inch pieces and cut the cheddar into small 1/4-inch cubes. Chop the parsley and set aside. Having everything prepped and ready makes assembly quick and ensures even distribution of flavors.

In a large mixing bowl, whisk together the sour cream, mayonnaise, salt, black pepper, vinegar, and Dijon mustard until smooth and well combined. I like to use quality sour cream and mayo here because they form the foundation of the salad—the better the base, the better the final result. The vinegar and mustard brighten the richness of the dairy, creating a perfectly balanced dressing.

Add the patted-dry peas to the dressing and stir in two-thirds of the mixture until the peas are evenly coated. Then fold in the crumbled bacon, diced red onion, cheddar cubes, and most of the chopped parsley (reserve a little for garnish). Stir gently but thoroughly to distribute all ingredients without breaking up the peas. This two-step dressing method prevents the salad from becoming too wet—you'll add the remaining dressing just before serving to keep everything fresh and creamy.

Just before serving, stir in the remaining one-third of dressing to refresh the salad and ensure a creamy consistency throughout. Taste and adjust seasoning if needed. Transfer to a serving dish and top with the reserved parsley for a fresh pop of color and flavor.