Peel and dice potatoes into small bite sized chunks.

In large pot add potatoes, celery and onion, and cover with water. Allow vegetables to boil on stove till potatoes are just fork tender.

Use colander to drain off water. Set vegetables aside. Rinse out pot and return to stovetop. Add butter to pot and allow to melt.

Add flour to the melted butter in the pot and stir till combined making a sandy play dough like texture.

Add milk to the flour dough in pot and stir constantly. Start with low heat and slowly increase to medium high heat. Continue to stir the roux for roughly 10 minutes. (Do not stop stirring or milk will scald.)

Once soup has thickened add back in potatoes, celery, onion, leftover or cubed ham, pepper and salt.

Allow soup to heat through, stirring occasionally. Serve topped with cheddar cheese or crumbled bacon and enjoy.