Preheat oven to 375ºF. In a 6 qt pan on medium heat, cover potatoes with water.
Season trimmed chicken with salt and pepper on both sides. In a large oven-safe skillet, heat oil over medium-high heat. Sear chicken 4 minutes per side. Remove from skillet and set aside.
On medium heat, add minced garlic and cook for 1 minute. Stir in thyme, crushed red pepper, chicken broth, and ½ cup heavy cream or half & half. Bring to a low simmer, stirring often for 5 minutes. Fold in parmesan and tomatoes. Return the chicken to skillet and coat with sauce.
Bake 15-18 minutes or until chicken is cooked through.
Meanwhile, when potatoes are fork tender, drain and mash with remaining ½ cup heavy cream or half & half, butter and salt to taste.
Plate potatoes then top with chicken and sauce. Garnish with parmesan and basil.