Preheat your oven to 375°F (190°C).

In a mixing bowl, combine the apple cider vinegar, honey, soy sauce, olive oil, minced garlic, salt, and pepper. Whisk until well blended.

Place the chicken breasts in a baking dish and pour the marinade over them, ensuring they are fully coated. Allow them to marinate for at least 30 minutes.

After marination, sprinkle the blackberries generously over the top of the chicken.

Bake in the preheated oven for 25-30 minutes or until the internal temperature reaches 165°F (75°C).

Let rest for about five minutes before serving.