Melt the butter in a large pot on medium high.
Add the chopped onion and cook for one minute until onion is soft.
Add the potatoes, and cook an additional 3-5 minutes, until they get a little color on them.
Pour in the chicken stock, and add the salt and pepper. Bring heat up to high.
Cook the soup for 15-20 minutes, until the potatoes are completely soft and easily pierced with a fork.
Turn off the heat, and use an immersion blender to carefully puree the soup. You can make it as smooth or chunky as you’d like. We prefer ours with some bite sized potato chunks.
Stir the bacon and cheese into the soup. Add additional salt or pepper to taste as needed.
Dish the soup up and top with chopped green onions.