Preheat oven to 160C. For braising liquor, heat oil in an ovenproof saucepan, add onion, garlic and ginger and cook over high heat until caramelised (10-15 minutes). Add remaining ingredients, bring to the boil and simmer for 10 minutes over low heat to infuse flavours.
Heat a large frying pan over medium-high heat, add oil, season beef cheeks to taste with sea salt and sear until browned (4-5 minutes each side). Add to braising liquor, cover with baking paper and foil and braise in oven until very tender and soft to touch (4-5 hours). Cool in liquor before removing beef cheeks from the pan.
Pass liquor through a fine sieve into a saucepan, skim fat from the surface, bring to the boil, add shallots and cook over high heat until reduced by half and onions are tender (14-15 minutes). Return beef to liquor to warm through, garnish with green onion and serve with red rice and kohlrabi salad.