Chop the potatoes and onions into small pieces.

In a medium saucepan on the stove top, place the potatoes, onion, and all but 1/4 cup of the milk over a medium heat. Let the mixture simmer until the potatoes are soft.

Using an immersion blender, blend the soft potatoes and onions until soup is creamy. You can leave a few chunks in the soup if that is the texture you prefer or blend it all the way for a creamy texture.

Mix the flour with the remaining milk and add into the simmering soup. Mix until the soup thickens.

Store any leftover soup in the fridge in an airtight container.