Season chicken breast on both sides with salt and pepper. Sear on both sides on medium-high heat, around 3-4 minutes, until crust builds. Remove from pan and let rest on a plate.
Allow pan to cool. Then return to medium heat, melt butter and sauté garlic until fragrant.
Add tomato paste and cook for 1 minute.
Add cherry tomatoes and oregano. Cook until soft and squish with spoon to release juices. Add spinach and cook until soft.
Add heavy cream and chicken broth. Let sauce come to boil and reduce to medium heat. Add Worcestershire sauce and S+P to taste.
Return chicken breasts and juices back to pan with sauce. Let sauce thicken and reduce for 10 minutes. Serve with long spaghetti and top with grated Parmesan and parsley.