Preheat the Oven: Preheat your oven to 375°F (190°C).
Prepare the Marinade: In a small bowl, whisk together the olive oil, lemon juice, dried basil, salt, and pepper. Set aside.
Butterfly the Chicken: Lay each chicken breast on a cutting board. Holding your knife parallel to the board, slice each breast horizontally, almost but not completely through, creating a pocket. Be careful not to cut all the way through.
Season and Marinate: Brush each chicken breast with the prepared marinade, ensuring they are well coated inside and out. Season the inside of each pocket with salt and pepper.
Prepare the Filling: In a skillet, heat 1 tablespoon of olive oil over medium heat. Add minced garlic and sauté until fragrant. Add chopped spinach and cook until wilted. Remove from heat and stir in crumbled feta, sun-dried tomatoes, oregano, and thyme. Mix well.
Stuff the Chicken: Spoon the spinach and feta mixture into the pockets of each chicken breast, pressing down gently to secure the filling. Use toothpicks to seal the openings.
Sear the Chicken: In an oven-safe skillet, heat some olive oil over medium-high heat. Sear the stuffed chicken breasts for 2-3 minutes on each side until golden brown.
Bake: Transfer the skillet to the preheated oven and bake for 20-25 minutes or until the chicken reaches an internal temperature of 165°F (74°C).
Serve: Once cooked, remove toothpicks and serve the Spinach and Feta Stuffed Chicken Breast with your favorite sides. Enjoy your flavorful and wholesome meal!