Preheat cast-iron skillet. Sauté veggies over med-high heat in butter, add all other ingredients, except bullion and water, stirring constantly. Mix bullion with water until dissolved, pour one cup water mixture into skillet; add flour to remaining water mixture (blend) until thick. Slowly add to skillet mixture until preferred consistency. Cook over medium heat until onions tender. May need to add little more water. Taste for season-appropriateness. Allow cooling in skillet; transfer to refrigerator container until needed. Will keep in fridge for one week.