Season both sides of chicken breast with 1 tsp oregano, salt, and pepper.

On medium-high heat, melt 4 tbsp butter, then add seasoned chicken breasts and cook for 4 minutes each side, or until no longer pink inside.

Remove chicken from the pan, set aside.

Add the remaining butter to the same pan, and cook onion, garlic, remaining oregano, and sun-dried tomatoes until onions are translucent.

Slowly add broth, cream cheese, and parmesan cheese and mix until smooth.

Reduce heat and simmer for 2-3 minutes. Add salt and pepper to taste.

Mix in fresh spinach and cover. Cook until wilted.

Add chicken to the sauce, and cover until chicken is reheated (about 2-3 minutes).