1. Preheat your oven to 375°F (190°C) and line a baking dish with parchment paper or lightly grease it with olive oil.
2. Prepare the filling by combining chopped spinach, sun-dried tomatoes, mozzarella, feta, minced garlic, Italian seasoning, salt, and pepper in a bowl. Mix gently until well combined.
3. Using a sharp knife, carefully slice each chicken breast horizontally to create a pocket—try not to cut all the way through. This step can be tricky at first; I remember Mama Lou’s steady hand guiding mine until I got the hang of it.
4. Stuff each chicken breast generously with the filling, pressing the edges gently to seal. If needed, use toothpicks to keep the filling inside while cooking.
5. Heat 2 tablespoons of olive oil in a large oven-safe skillet over medium-high heat. Once hot, add the stuffed chicken breasts and sear for 3-4 minutes on each side until golden brown. This step locks in the juices and gives the chicken a beautiful color.
6. Transfer the skillet to the preheated oven and bake for 20-25 minutes, or until the chicken is cooked through and the cheese inside is melted and bubbly. You’ll know it’s done when the internal temperature reaches 165°F (74°C).
7. Optional: In the last 5 minutes of baking, sprinkle grated Parmesan cheese over the top for a golden, crispy finish.
8. Remove from oven and let rest for 5 minutes before slicing. Garnish with fresh basil leaves for a pop of color and freshness.

One tip I picked up from Mama Lou is to always let the chicken rest after baking. It allows the juices to redistribute, keeping every bite tender and juicy—a simple step that makes a world of difference.