Use a sharp paring knife to carefully cut a horizontal pocket into each chicken breast, avoiding cutting all the way through, then pound each piece with a mallet until about 1.5 cm thick. This ensures even cooking and a good surface for stuffing.
Combine chopped spinach, shredded cheese, minced garlic, chopped herbs, salt, and pepper in a bowl, mixing well to create a flavorful filling. Taste and adjust seasoning if needed.
Spoon a generous amount of the filling into each pocket, then seal the opening with toothpicks or tie with kitchen twine to keep the filling inside during cooking.
Heat a skillet over medium-high heat, add a splash of olive oil, and once hot, sear each stuffed chicken breast for about 3-4 minutes per side until golden brown and crispy.
Transfer the skillet to a preheated oven at 200°C (390°F) or move the chicken to a baking dish, then roast for 20-25 minutes until the internal temperature reaches 75°C (165°F) and the filling is bubbling.
Remove the chicken from the oven and let it rest for about 5 minutes. Carefully remove the toothpicks or twine, then slice each piece to reveal the gooey, cheesy filling inside.
Serve hot, drizzled with a little olive oil or a squeeze of lemon, and enjoy the juicy, crispy, cheesy goodness of these stuffed chicken breasts.
