Heat oven to 375°F. Lightly grease a 2-quart baking dish (or an 8x11-inch casserole).
In a large skillet over medium heat, cook the chopped bacon until crisp, 7–9 minutes. Transfer bacon to a paper towel–lined plate; leave about 1 tablespoon of the rendered fat in the pan (pour off the rest).
Add the onion to the skillet and cook in the bacon fat until golden at the edges, 4–5 minutes. If using ground beef, add it to the onions and cook, breaking it into small crumbles, until browned and no longer pink, 4–6 minutes. Drain excess grease, leaving a thin coating in the pan.
Stir in Worcestershire, black pepper, ketchup, mustard, brown sugar, and garlic powder. Cook, stirring, until glossy and slightly thickened, about 2 minutes—this quick simmer helps the flavors meld.
Fold in the baked beans, then add hot sauce and apple cider vinegar. Bring just to a simmer for 1–2 minutes to warm through.
Scrape the mixture into the prepared baking dish. Stir in half of the crispy bacon and scatter the remaining bacon over the top.
Bake uncovered for 20 minutes to lightly caramelize the surface. Cover loosely with foil and continue baking 10–15 minutes more, until bubbling and thickened around the edges.
Optional finish: Broil 1–2 minutes for extra toasty bacon on top. Let the beans rest 10 minutes before serving so the sauce sets. Tip: If your beans seem looser than you like, remove the foil for the last 5 minutes of baking to evaporate a bit more moisture.