for serving: chopped green onions, chopped cooked bacon, sour cream, and cheese(optional)
Use the sauté function on your instant pot to melt the butter (2 tablespoons). Add the diced onion and stir to coat. Sauté for about 2 minutes, stirring occasionally, until onions are softened.
Add the chicken broth (4 cups), diced potatoes (2.5 lbs.), kosher salt (1.5 teaspoons), and black pepper (1/2 teaspoon). Stir together.
Turn sauté function off and place cover on instant pot, making sure the valve is set to "sealing." Set pressure cooker to manual, high pressure for 10 minutes.
When the 10 minutes is up, quick release the pressure by using a wooden spoon to turn the valve from "sealing" to "venting." Wait until the float valve depresses completely until you open the pressure cooker (this can take about 5 minutes).
Use an immersion blender to puree the soup directly in the pot. (Alternatively, use a potato masher for a more rustic texture.)
Add the sour cream (8 oz.) and the shredded cheddar cheese (1 cup) to the pot and stir together until melted. Taste and adjust seasoning if necessary.
Serve garnished with sliced green onions, chopped cooked bacon, more sour cream, and more cheese, if desired.
For a vegetarian version, be sure to use vegetable broth instead of chicken.
If you don't have an immersion blender, or if you want a more rustic texture, you can just use a potato masher to mash the potatoes. You can also use a standing blender in batches.
To cut down on food waste, you can cook bacon in the pressure cooker and use 1-2 tablespoons of the leftover grease instead of butter, and chop the bacon for serving. You can also add the white parts of the green onions to the diced yellow onions.
Slow cooker directions: Place the onions, potatoes, chicken broth, salt, and pepper in your crockpot and cook on low for 6-8 hours or high for 3-4 hours. Puree, then stir in the butter, sour cream, and cheese.
Stovetop directions: Sauté the onions in butter in a large pot, then add the potatoes, chicken broth, salt and pepper. Bring to a boil, cover, and simmer on low for 30-45 minutes, or until potatoes are tender. Puree, then stir in sour cream and cheese.
I made this in my 6 qt. Instant Pot. You may have to cut the ingredients in half for a mini IP, or adjust the cooking times if you have a different brand pressure cooker.