Step 1:
Preheat your oven to 400°F (200°C). Lightly grease a baking dish or line it with parchment paper for easier cleanup.

Step 2:
Prepare the spinach and ricotta filling. In a medium bowl, combine the ricotta cheese, chopped spinach, shredded mozzarella, Parmesan, minced garlic, onion powder, basil, oregano, salt, and pepper. Mix until everything is well combined and creamy.

Step 3:
Place the chicken breasts on a cutting board. Using a sharp knife, make 5 to 6 deep slits across each breast, being careful not to cut all the way through. The cuts should go about three-quarters of the way down to create slots for stuffing.

Step 4:
Drizzle the chicken with olive oil and season generously with salt and black pepper on both sides, including inside the slits.

Step 5:
Spoon the spinach and ricotta mixture into each slit, pressing gently so it fills the space without overflowing too much. Try to distribute the filling evenly across all the cuts in each chicken breast.

Step 6:
Place the stuffed chicken breasts in the prepared baking dish. If you’re feeling cheesy, sprinkle a little extra mozzarella over the top for a golden finish.

Step 7:
Bake uncovered for 25 to 30 minutes, or until the chicken is fully cooked (internal temperature should reach 165°F). The cheese should be melted and slightly golden.

Step 8:
Remove from the oven and let rest for 5 minutes before serving. Garnish with chopped parsley or a pinch of red pepper flakes if you like a little heat.