In a medium bowl, whisk together the fresh lemon juice, olive oil, minced garlic, lemon zest, dried oregano, salt, and black pepper to create the marinade.
Place the chicken breasts in a large resealable plastic bag or shallow dish and pour the marinade over the chicken, ensuring all pieces are coated evenly.
Seal the bag or cover the dish and refrigerate for at least 2 hours, preferably overnight, to allow the flavors to infuse.
Preheat the oven to 400°F (200°C).
Remove the chicken from the marinade and place the breasts in a baking dish.
Pour the chicken broth into the baking dish around the chicken breasts.
Bake the chicken uncovered for 30 minutes, or until the internal temperature reaches 165°F (74°C).
Remove the chicken from the oven and transfer the breasts to a serving plate.
Place the baking dish on the stovetop over medium heat and add the unsalted butter to the pan juices.
Stir the pan juices and butter together, cooking for 2-3 minutes until slightly thickened to make a sauce.
Pour the sauce over the chicken breasts.
Garnish with chopped fresh parsley before serving.