Trim the chicken from any excess fats. Slice the each breast in half horizontally. Salt and pepper the chicken.
Bring a large non-stick skillet to medium high heat. Add in the olive oil and pan sear the chicken on each side for about 5 minutes until golden. Remove and set aside. Cover with foil wrap.
In the same skillet, add 1 tbsp. of olive oil and sauté the diced onions until tender. Add in the minced garlic and sauté for about 30 seconds until fragrant.
Add in the sundried tomatoes, sundried tomato pesto, salt and spices. Mix and sauté the mixture for about 1 minute.
Add in the heavy cream, milk, chicken broth and mix. Simmer for a couple or minutes until the sauce starts to thicken up.
Throw in a handful of spinach and cook on medium-low heat for a couple of minutes. Taste to adjust salt and pepper.
Add the cooked chicken pieces back into the sauce and drench the chicken with the sauce mixture. Cover and let them cook together on low heat for 2-3 more minutes.
Remove from the heat, garnish with some fresh chopped parsley or parmesan cheese and serve.