In a medium Dutch oven heat a tablespoon of oil, add the onion, peppers and garlic. Saute until translucent, do not brown. Remove and set mixture aside.
Lightly grill the tomatillos on open flame until lightly charred. Remove from heat, place in bowl. Using a food process or blender, add sauteed peppers and onion and tomatillos and blend till smooth.
Pour into stainless steel saucepan and add the wine, vinegar, and chicken stock and seasoning. Heat till just boiling.