Saute until onions are clear:
half stick butter
potatoes, peeled and chopped
Cover with water and cook 20 minutes or so until potatoes are tender. Add salt and pepper.
Use a stick blender to mush up the soup about 2/3 of the way.
Add some half and half, heavy cream, or milk, whatever you have.
Add shredded cheddar cheese.
Serve with fresh, chopped cilantro and hot sauce.