Combine first 6 ingredients. Bring to a boil. Reduce heat and simmer 20 minutes. Melt margarine over low heat; add flour to blend. Cook, stirring constantly, for 3 minutes to make a blonde roux.
Strain liquid from potato, chile and onion mixture. Reserve other half. Stir reserved liquid into roux. Raise heat, stirring with a whisk until thick, Add milk to thickened liquid and continue until it comes to a simmer. Turn off heat. Add mashed potato, chile and onion mixture. Stir in and blend. Add reserved cubed potatoes, chile and onion.
Serve with shredded Cheddar cheese on top.
Gumbos, Soups, Chowders
Cajun Country -- New Iberia, Louisiana