In a pan set over a medium heat, add the oil and half of the butter, and allow the butter to melt.
Add the chicken breasts, season them with salt and pepper, fry on one side until golden, then turn onto the other side, place the lid on, and leave it to cook again until the other side is golden too, and the chicken is cooked through.
Remove the chicken from the pan, and set aside.
Add the remaining butter, peeled and chopped garlic, and fry it for 30 seconds until it releases its flavour.
Quarter the tomatoes, and add them to the garlic - leave to cook for 2-3 minutes until the tomatoes are slightly mushy.
Add the spinach, give it a good stir, then in go the cream, parmesan, oregano, season with salt and pepper, and leave it to simmer for 2-3 minutes.
Return the chicken to the pan, place the lid on for 2 minutes, then garnish with fresh parsley and serve hot!