Blitz marinade ingredients together until smooth.
Place ribs in a large bowl and toss with half the marinade.
Marinade overnight or for at least 4 hours.
Preheat oven to 160°C.
Place ribs on a bed of onion slices in a roasting tray.
Pour beer into tray and season liberally.
Cover with foil and roast for 3 hours.
Increase oven temperature to 200°C.
Remove foil and baste ribs with reserved marinade.
Roast for 30 minutes, until browned.
Serve with a side of your choice.