One good recipe for old-fashioned potato soup includes potatoes and chopped onion in a cream base made with butter and evaporated milk. Season the soup to taste with salt and freshly ground black pepper. Topping with shredded cheese as a garnish is optional.
Prepare the soup by peeling and dicing 2 pounds of russet potatoes (approximately six potatoes) and tossing them with 1/2 cup of chopped onion, 3 tablespoons flour, and salt and pepper. Set these ingredients aside as you melt 1/4 to 1/2 cup of butter in a large Dutch oven. Add the potatoes and onions to the butter, and stir to coat everything.
Cover the potatoes with water, and bring the pot to a boil. Add one 12-ounce can of evaporated milk; reduce the heat so the contents continue to simmer, and stir the pot occasionally. Check the potatoes for tenderness after 25 to 30 minutes. Taste the soup and adjust the seasonings as necessary. Continue to simmer until the soup thickens.
If you prefer a smooth potato soup, use an immersion blender to puree the potatoes once they are tender. Serve the soup in bowls garnished with cheese, green onions and toasted croutons. For a hearty meal, serve the soup in sourdough bread bowls.