Preheat your oven to 375 degrees f.
Rub your chicken breasts with oregano, garlic powder, sea salt, and pepper to taste on all sides.
Slice each chicken breast down the middle lengthwise, but don’t go all the way through. Just enough to create a large pocket for your fillings.
Stuff the pockets evenly with your cheese slices, jalapeno slices, then using a spoon, add your slightly smashed blackberries.
Insert toothpicks if needed to hold everything together.
Heat your oil in a large oven-safe skillet over medium heat. Add the chicken and carefully sear until beautifully golden-brown on both sides, about 4 minutes on each side.
Add the wine or broth to the skillet to deglaze and create more flavor, then transfer it into your preheated oven.
Bake in your preheated oven for 12-15 minutes or just until your chicken is cooked through to 165°F (73.9°C) as measured by a food thermometer.
Garnish with freshly chopped parsley or basil.