Start by preheating your oven to 425°F. Grease a large baking dish with a light coating of olive oil.
Chop the celery and onions into small pieces. Get out a large nonstick pan, add a drizzle of olive oil, and the chopped celery, onions, garlic, rosemary, and pecans. Sauté on medium heat until the veggies are soft.
Cube the gluten-free bread and add to a bowl. Whisk the eggs, olive oil, salt, and pepper in a separate bowl, then pour them over the bread mixture. Add the bread mixture to the pan and cook for another 5 minutes to fully cook the eggs.
Using a sharp knife, carefully butterfly the chicken breasts, creating a pocket without cutting all the way through. Season the chicken generously with garlic powder, salt, and pepper.
Spoon the stuffing mixture into each chicken breast pocket, packing it tightly but ensuring it doesn’t overflow. Secure the edges with toothpicks if needed. Transfer the seared chicken breasts to your prepared baking dish. Bake for 20-25 minutes, or until the internal temperature of the chicken reaches 165°F.
Serve with your favorite sides & enjoy!