Prep the chicken. Pat the chicken breasts dry and place them on a cutting board. Using a sharp knife, cut a pocket into the thickest side of each breast, keeping the other sides intact. Season the outside with salt, pepper, and half the Italian seasoning.

Make the quick Alfredo filling. In a skillet over medium heat, melt the butter and sauté the garlic for 30–60 seconds until fragrant. Stir in the heavy cream and bring to a gentle simmer. Add cream cheese and whisk until smooth. Fold in Parmesan, onion powder, remaining Italian seasoning, and a small pinch of red pepper flakes. Stir until thick and creamy.

Add spinach. If using, stir in chopped spinach until just wilted. Taste and adjust salt and pepper. Remove from heat and let the mixture cool for a few minutes so it thickens slightly.

Stuff the chicken. Spoon the Alfredo mixture into each breast pocket, dividing evenly. Don’t overfill. Secure the openings with toothpicks or tie gently with kitchen twine.

Sear for flavor. Preheat the oven to 375°F (190°C). Heat oil in an oven-safe skillet over medium-high heat. Sear the stuffed chicken 2–3 minutes per side until lightly browned.

Top with mozzarella. Sprinkle shredded mozzarella over the tops of the chicken breasts.

Bake until done. Transfer the skillet to the oven and bake 15–20 minutes, or until the thickest part of the chicken reaches an internal temperature of 165°F (74°C). Rest for 5 minutes before slicing.

Finish and serve. Garnish with chopped parsley and extra Parmesan if you like. Serve with zucchini noodles, roasted broccoli, or a crisp Caesar-style salad.