Next with the flame on medium heat, add the remaining butter and oil. Saute the shallots for 3-4 mins, season as desired with salt and pepper; add mushrooms, tomatoes, white wine and tomato sauce. Bring to a slow simmer and then add cream. Cook for an additional 2-3 mins, then return the chicken to the pan. Coat through the sauce... Continue to simmer for an additional few minutes. Serve warm.