In a non stick pan, heat up 1 tbsp of olive oil.Brown the chicken on both sides for a few minutes.Salt and pepper to taste and set aside.In a roasting pan, melt the butter with 1 tbsp of olive oil.Add the carrots and cook 5 minutes.Add the celery and cook fo another 3 minutes.Add onion, garlic and mushroom cook for 3 minutes.Add the flour, smoked paprika and provencial herbs.Cook for 2 minutes.Add the broth and mix well.Add the tomatoes and the bay leaf.Stir to mix all ingredients.Add the chicken on top of mixture, cover and bake in a preheated oven at 350F for about 2 hours.