Toss vegetables in oil. Place in a large roasting pan. Roast at 425 degrees for 30 minutes or until vegetables start to caramelize. Add flour to vegetables; stir until distributed among the vegetables. Add broth,2 tablespoons of butter and 1 tablespoon of instant chicken bouillon granules and continue roasting until sauce is thick.
Remove from oven and strain. Adjust seasoning. Keep warm in a crock pot. Serves 8-10. Thin with hot chicken broth if necessary.
I normally make another 1/2 of this recipe to have enough for leftovers.