Bring a large saucepan of salted water to the simmer over medium heat, add beetroot, simmer until tender (45-55 minutes), drain, then set aside until cool enough to handle. Peel and slice into 5mm-thick rounds, set aside until required.
Meanwhile, bring a saucepan of salted water to the boil, add cauliflower, cook until just tender (8-10 minutes), drain and set aside to cool.
Meanwhile, for braised onion, heat oil in a frying pan over medium-high heat, add onion and stir occasionally until caramelised (15-20 minutes). Deglaze pan with vinegar, season to taste and set aside to cool.
Preheat oil in a deep-fryer or deep-sided saucepan to 180C. For beer batter, place flour in a bowl, whisk in lager and a pinch of fine salt until a smooth batter forms. Dust cauliflower and beetroot with seasoned flour, dusting off excess, then dip in batter, shaking off excess. Deep-fry in batches, turning occasionally with a slotted spoon, until crisp and cooked through (3-4 minutes; be careful as hot oil may spit). Drain on absorbent paper, season to taste with sea salt and serve hot with braised onion and lemon wedges.
This recipe is from the August 2010 issue of Australian Gourmet Traveller.