Place potatoes and onion in a large Dutch oven and add enough chicken broth to cover potatoes. Season with salt and pepper. Bring pot to a boil and simmer until potatoes are tender, about 12 minutes. Use an immersion blender or potato masher to get soup to desired consistency. Add milk and sour cream and stir until combined.
Reserve ½ cup of Kerrygold Aged Cheddar for topping.
Add remaining cheese by the handful and stir until completely melted. Simmer over low heat for 5 minutes to let flavors meld.
Ladle into bowls and divide the bacon, green onions and cheddar cheese between the bowls.
This soup freezes well! Make it ahead of time and freeze for busy nights on the run!