Directions
Create the creamy filling. Melt butter in a pan over medium heat.
Sauté the chopped onion for 1-2 minutes until fragrant, then add the chopped spinach and cook until wilted, about 2 more minutes.
Stir in the cream cheese until it melts into a smooth, combined mixture.
Remove from heat and set aside.
Prepare and stuff the chicken.
Place the chicken breast flat on a cutting board. Carefully slice a deep pocket into the thickest side of the breast, being careful not to cut all the way through.
Season both the outside and inside of the pocket generously with salt and pepper. Spoon the spinach and cream cheese mixture into the pocket, then top with the grated mozzarella cheese.
Sear and cook the chicken. Secure the opening of the chicken breast with a few toothpicks to keep the filling inside.
Heat olive oil in a skillet over medium-high heat. Carefully place the stuffed chicken in the hot skillet and sear for 4-5 minutes per side, until golden brown.
Reduce the heat to medium-low, cover the pan, and cook for another 6-8 minutes, or until the chicken is cooked through and the internal temperature reaches 165°F / 74°C.
Let it rest for 5 minutes before slicing and serving hot.
