Pat chicken breasts dry and season both sides with salt and pepper. In a large skillet over medium-high heat, heat olive oil and 1 tablespoon butter until shimmery. Sear chicken breasts 2-4 minutes on each side, turning once until golden-brown. Transfer to a plate and set aside.
In same skillet over medium-high heat, saute garlic, rosemary and thyme sprigs, basil and bay leaf 1-2 minutes or until fragrant. Reduce heat to medium and add wine and let cook 1 minute. Stir in tomato paste, crushed tomatoes, diced tomatoes, and chicken broth until smooth.
Bring tomato mixture to a simmer over medium-high heat then nestle chicken back into pan, making sure it's nearly submerged in the sauce. Reduce heat to medium-low, cover pan and let simmer over medium-low heat 45-60 minutes or until chicken is fall-apart tender.
Remove rosemary sprigs, thyme sprigs, basil leaves, and bay leaf from sauce and discard. Toss spinach into hot tomato sauce and chicken until wilted then stir in butter until melted.
Serve chicken and sauce hot over hot pasta and top with shaved Parmesan and additional basil if desired. Enjoy!