Hamburg Steak with Smoked Onions

Directions

1. Trim the roots and tops from the onions and slice across the rings into 4 equally thick pieces.
2. Preheat the FORCE™ BBQ, with the grill on one side (set to medium) and the cast iron plate on the other. Place the wood chips on top of the cast iron plate and rub both sides of the onion slices in a little grapeseed oil. Season the onions with salt and place onto the grill, closing the lid. After 5 minutes, flip the onions and close the lid again as quickly as possible to trap the smoke. Cook for an additional 5 minutes until the onions have softened and caramelised. Remove the onions set aside onto a tray to cool. Discard the wood chips. Once cooled, remove the centre portions of each onion slice and set aside 100g for use in the Hamburg mix. Reserve the remaining onion rings.
3. To prepare the patties, combine the diced chuck with the salt. Cover and place in the fridge for 6 hours. In the meantime, combine the short-rib and brisket. Mix in the reserved 100g caramelised onions. Use a meat grinder fitted with a 3mm plate and grind the mixture twice. Cover and place in the fridge for several hours until completely chilled.
4. Combine the ground mixture with the diced chuck. Cover a chopping board with a double layer cling film and position under the mouth of the grinder. Replace the 3mm plate with an 8mm plate and pass the mixture through the grinder. Have a helper to assist in gently laying the strands of meat that comes out of the grinder onto the cling film, ensuring the grain remains lengthwise in the same direction without tangling. Once done, wrap the meat tightly in the cling film, twisting the ends to form a compact log. Release any trapped air by pricking the cling film. Continue to twist the ends until the log is 12cm diameter. Wrap the log in one more layer cling film and place in the fridge until chilled thoroughly. Place the still-wrapped log onto a chopping board and slice 150g-portion patties from the log. Set aside onto a tray until ready to cook.
5. For the mustard sauce, heat the reduced beef stock in a pan over moderate heat and add the parsley stalks, mustard and vinegar. Remove from the heat and allow to stand for 10 minutes before removing and discarding the parsley.
6. To finish and cook the patties, remove and discard any cling film that may still be wrapping the individual patties. Gently press the patties, shaping them into a burger shape approx. 2cm thick. Lightly coat the cast iron plate of the FORCE™ BBQ, set to high, with grapeseed oil. Cook both sides of the patties, flipping every 20 seconds until the crust has caramelised and the core reads 55°C when probed. Reheat the onion slices at the same time by placing them on the grill alongside the patties.
7. Serve the Hamburg steak with the hot smoked onion rings and mustard sauce.