Add the fresh spinach to a large, dry pan. Turn on the heat and cover the leaves until they wilt – the heat will get them to release water and the steam will wilt the spinach. You don't need any oil or water.
Once the spinach has wilted (reduced in size), chop the spinach into smaller pieces. Also, chop the sundried tomatoes and basil leaves into small pieces. Mix them with the cream cheese, parmesan, mozzarella, oregano, lemon zest, garlic powder, and chili flakes.
Make a single long cut horizontally through the middle of the chicken breast, ensuring you stop before cutting entirely through the meat. You need to form a pocket (refer to the image on the post).
Season the chicken breast from all sides and inside with the paprika, salt, pepper, 1 Tbsp of olive oil, and the lemon juice.
Fill each of the chicken breasts with ¼ of the spinach and cheese mixture until all the mixture has been used between the 4 breasts. Be careful not to over-stuff.
In a large pan or skillet, add 3 Tbsp of olive oil and saute the stuffed chicken breasts on medium-high heat, turning them on both sides until you achieve a golden brown exterior. Then, put the pan directly into the oven and bake at 375ºF/190ºC for a further 20 minutes to ensure the inside is cooked.
When fully cooked, the chicken will have an internal temperature of 165°F/74°C. Check the thickest part of the chicken with a meat thermometer or ensure the juices run clear when pierced with a fork/knife before removing it from the oven.
Notes
To Store In The Fridge: Allow the chicken breasts to cool, then place them in an airtight container. They’ll keep for up to 4 days.In The Freezer: Transfer the cooled chicken into a Ziplock bag or a freezer-safe container. You may want to wrap it in plastic wrap or foil before placing it in the container or bag to prevent freezer burn. They’ll keep for up to 3 months.To Reheat: Leave the stuffed chicken breasts in the fridge to defrost overnight. Reheat in a pan with a little oil until the chicken has browned a little more and warmed through or heat through in the oven. You may want to cover it with foil to prevent any more cooking. Check the blog post for serving suggestions!