Preheat oven to 400 degree.
Slice chicken breasts through the middle but not separating the meat—a butterfly cut.
In a ziploc bag, toss chicken breasts with olive oil, salt, black pepper, garlic powder, and onion powder; place chicken in a baking dish.
Place chicken in the oven, turn the heat down to 375 degree, and bake for 30 minutes.
Melt butter; whisk melted butter, ketchup, steak sauce, apple cider vinegar, and brown sugar together.
Spread sauce on chicken and bake for an additional 15 minutes; broil for five minutes—until BBQ sauce is bubbly!