Step 1: Preheat oven to 375°F (190°C).
Step 2: Butterfly each chicken breast by slicing horizontally, creating a pocket.
Step 3: Season chicken on both sides with garlic powder, smoked paprika, salt, and pepper.
Step 4: In a skillet, heat ½ tbsp olive oil over medium heat. Add garlic and spinach; cook 2 minutes until wilted.
Step 5: Remove from heat and stir in cream cheese, mozzarella, Parmesan, Italian seasoning, and lemon juice until creamy.
Step 6: Stuff each chicken breast with the spinach mixture. Secure with toothpicks.
Step 7: In an oven-safe pan, heat remaining olive oil. Sear chicken 3–4 minutes per side until golden.
Step 8: Transfer skillet to oven; bake 20–25 minutes or until internal temperature reaches 165°F (74°C).
Step 9: Rest 5 minutes before serving. Slice and enjoy warm.