Add the bacon to the skillet and cook, stirring, until the fat is rendered, 2 minutes. Drain off the fat. Add the remaining 1 1/2 tablespoons of oil to the skillet and stir in the flour until incorporated. Add the onion and garlic and cook over moderate heat, stirring, until slightly softened, 3 minutes. Add the tomato and tomato paste and cook, stirring, until the tomato softens slightly, 5 minutes. Add the milk and broth and bring to a boil, stirring until slightly thickened, 3 minutes. Return the chicken and any accumulated juices to the skillet; add the parsley sprigs.