Step 1

Add the butter and olive oil to a large skillet over medium heat. Season the chicken breasts generously on both sides with salt and pepper. Once the butter and oil are hot, add the chicken breasts and cook for 4-5 minutes on each side until nicely browned.

Step 2

Remove the chicken to a plate and cover with foil to keep warm.

Step 3

Add the onion to the same skillet and cook for 3-4 minutes to soften, then add the garlic and cook for 1 minute longer. Sprinkle in the flour, stir and cook the flour out for 1 minute. Pour in the wine to deglaze the pan, scraping up the brown bits from the bottom of the skillet.

Step 4

Add the heavy cream, half and half, parmesan cheese and salt and pepper to the skillet. Stir and bring to a simmer for 2-3 minutes to let the sauce thicken. Stir the spinach and stir into the sauce to wilt, then add the diced tomatoes.

Step 5

Test the sauce for seasoning, then add the chicken breasts back to the skillet, tucking down into the sauce. Spoon some of the sauce over the chicken and gently simmer for 7-8 minutes until the chicken is cooked through.