Preheat the oven to 400 degrees F. Lightly grease a baking dish with olive oil or line with parchment paper or aluminum foil.

Place each chicken breast on a cutting board. Using a sharp knife, make horizontal slits about ¾ of the way through each breast, spacing the cuts about ½ inch apart. Be careful not to cut all the way through.

Salt and pepper both sides of chicken breast. Set aside for now.

Depending on the amounts of slices in your chicken, cut canadian bacon in half or thirds to ensure you have enough.

Stuff each slit with canadian bacon and set aside.

In a medium-sized bowl, combine the chopped spinach, sun-dried tomatoes, mozzarella cheese, Parmesan cheese, garlic, oil from sun-dried tomatoes, oregano, and garlic salt. Mix well until all ingredients are evenly combined. Add more oil if you have trouble grabbing ingredients. You want just enough to help bring the mixture together.

Stuff each slit in the chicken breasts with the spinach mixture, pressing the filling down firmly into each cut.

Transfer the stuffed chicken breasts to the prepared baking dish. If there is any remaining filling, distribute it evenly over the tops of the chicken breasts.

Place the baking dish in the preheated oven and bake for 15-25 minutes, or until the chicken is cooked through and the internal temperature reaches 165 degrees F. Depending on the size of your chicken breast, the cook time will differ. I recommend starting to check at 15 minutes and going from there.

Remove the chicken from the oven and let it rest for 5 minutes before serving. If desired, sprinkle with fresh chopped parsley for added flavor. Best when served warm.