Add mayo and sour cream into a medium bowl and mix well. Once the two are well mixed, add in 1/4 cup cheddar cheese, 1/4 cup green onion tops, black pepper, celery seed, parsley, and salt. Mix well and then place in the refrigerator.
Cut and cube your baking potatoes. I like to peel 3 and leave one with the peel on for added flavor. Add cubed potatoes to a large pot and cover with water. Bring to a boil and boil for 20 minutes until soft, but not too soft.
Drain potatoes and lightly mash, leaving chunky. Add in the prepared mixture with the remaining cheese. Top with green onion tops and chopped bacon bits. Serve immediately.
**Nutrition facts are based on my best estimation for this recipe. They may not be accurate depending on what brands you use or modifications you might make to the recipe. For most accurate calculations, I recommend using a nutrition calculator with the exact brands and measurements you use with the recipe.