For the pickled mooli, add the beetroot juice, sugar, vinegar and water to a saucepan and bring to the boil. Remove from the heat and set aside to cool.
Dice enough mooli to produce two heaped tablespoons. Cut the remainder into thin discs, enough for ten per serving. Add the diced mooli to a pan of boiling salted water for half a minute. Refresh in iced water until chilled, then drain. Repeat this separately with the mooli discs.
Put the discs and dice in different containers and add the cooled pickling liquid. Pickle in the fridge for at least 4 hours. The pickled mooli will keep for 5-7 days if it is refrigerated.
Heat the oil to 180°C in a deep pan. Add the quinoa, fry until crisp whilst stirring, then remove from the pan and drain on absorbent paper. Season with salt, then leave to one side.
For the tartare, first allow 10-15 minutes for the beef to firm up in the freezer, however it must not freeze.
In the meantime, finely chop the horseradish shoots and keep the stems for the garnish. Finely chop the shallots, rinsing them quickly in cold water, then drain them and carefully squeeze them dry. Set them both aside.
Take the beef out the freezer and cut into small cubes using a very sharp knife. Place in a bowl and season with salt and pepper. Add the horseradish shoots, shallots and desired amount of wasabi paste, to taste. Drain and then add the diced pickled mooli. Mix well to combine.
Refrigerate the tartare mix for 10 minutes, remove and check the seasoning – the initial seasoning will have lessened slightly, so re-season if required. Place four 6 cm rings on a lined tray. Add 80-90 g of the mixture to each ring and shape. Refrigerate for another 10 minutes to set.
While the tartare mix is setting, make the wasabi mayonnaise by mixing your desired amount of wasabi paste together with the mayonnaise. Decant into a squeezable bottle, ready to serve.
Form a circle of pickled mooli discs on the plate. Take the tartare out of the fridge and transfer to the centre of the mooli discs with a spatula. Top with the quinoa and carefully remove the ring. Dot the wasabi mayonnaise on top of the quinoa, then add the radish slices and horseradish stems. Drizzle with a small amount of olive oil and serve immediately.