Wash hands with soap and water.
Scrub the potatoes with a clean vegetable brush under running water. Once clean, peel and cube the potatoes.
In a large pot, boil potatoes until they can be pierced with a fork. Remove from heat and drain the excess water. Mash potatoes until they reach a lumpy consistency.
In a separate pan melt the butter. Add flour and cook over low heat while stirring. After a minute, add half the milk (3 cups) and stir until the lumps are out of the flour mixture.
Wash hands with soap and water after handling raw flour.
Add the remaining milk (3 cups) and turn up the heat to medium high. Heat to a boil while stirring continuously
After boiling, turn the heat off and add the remaining ingredients including the mashed potatoes and stir.
When reheating leftover soup, reheat it until internal temperature reaches 165 °F on a food thermometer.