Preheat oven to 375° F. Line a baking sheet with foil or parchment paper and set aside.
Heat olive oil to medium heat in a large skillet or nonstick pan. Add celery, onion, ½-tablespoon Italian seasoning and salt and pepper to taste. Cook until tender, 5-7 minutes, stirring often.
Stir in spinach, dried apricots and panko crumbs. Cook 2-3 minutes more, until spinach is wilted. Remove from heat.
On a flat surface, pound chicken breasts flat with a mallet to about ¾-inch thick. Remove breasts and carefully cut a slit horizontally into the sides to create a pocket; do not cut completely in half.
Evenly stuff with prepared stuffing mixture. Lightly sprinkle both sides with salt and pepper, and remaining Italian seasoning. If desired, secure opening with toothpicks.
Place on prepared baking sheet with space between them. Bake for 20-25 minutes, or until internal temp reaches 165 F. Let rest 5 minutes and serve.
Pound chicken breasts in a Ziploc bag or covered in plastic wrap for easy cleanup.
Pound the chicken with a meat mallet or rolling pin to make them larger and flatter.
When cutting a pocket to stuff be careful not to cut the chicken in half.
You can prep the chicken in advance, stuff them with the filling and keep in the fridge 1-2 days covered until you are ready to bake.
Whole wheat breadcrumbs are a more nutritious alternative to white breadcrumbs.
Use GF breadcrumbs if needed.
Use a meat thermometer if unsure the chicken is cooked through.
Leftovers can be stored in a sealed container in the fridge for 2-3 or freeze for longer storage.