1. Preheat your oven to 375°F (190°C). Lightly grease a baking dish with olive oil and set aside.
2. Place the chicken breasts on a cutting board, and using a sharp knife, make a horizontal cut through the center of each breast to create a pocket. Be careful not to cut all the way through.
3. In a small bowl, combine the spinach, feta cheese, and sun-dried tomatoes. Season with oregano, salt, and pepper, and mix well.
4. Spoon the spinach mixture into each chicken pocket, dividing it evenly among the breasts. Roll up each chicken breast tightly and secure with toothpicks or kitchen twine.
5. Heat the remaining olive oil in a large skillet over medium heat. Add the chicken rolls and sear on all sides until golden brown, about 3-4 minutes per side.
6. Transfer the chicken to the prepared baking dish and bake in the preheated oven for 20-25 minutes, or until the chicken is cooked through and the juices run clear.
7. Let the chicken rest for a few minutes before removing the toothpicks or twine. This resting time helps the flavors meld beautifully.

These steps might remind you of how my abuela and I would carefully roll out tortillas, a process that was as much about the tactile experience as it was about the taste. Take your time and enjoy the process!