Add Tomatoes, and Stock, mix well. Cover bring to a simmer, reduce heat to medium low, simmer for 1 hour, stirring occasionally. Add Potatoes, bring back to a simmer, cover, simmer for 1 more hour.
Roux:
- In a small skillet on medium heat, add Butter. Allow Butter to melt and stop bubbling, (2 minutes). Add in Flour, stir constantly for 3 minutes. Add Roux to pot, mix until Sauce thickens.