01 - Heat oven to 375°F and prepare a rimmed tray. Peel onions, halve and separate matching outer layers. Mix beef, cheddar, crumbs, egg and seasonings evenly.
02 - Divide filling into small portions that fit between paired onion layers. Wrap each with one or two bacon slices as available, keeping portions modest; bake excess filling separately if necessary. Count any toothpicks.
03 - Brush with barbecue sauce and bake about forty to forty-five minutes, checking thick centers reach 165°F because the parcels include turkey bacon. Shield the glaze if it darkens first.
04 - Rest briefly and remove fasteners before serving. Avoid a broiler finish on parchment or unsuitable cookware.