In a bowl, combine the kohlrabi, carrot, beetroot and sugar. Mix well and set aside for 10 minutes, then drain. Place a frying pan over high heat add the oil and fry the garlic until fragrant. Add the beef, season with pepper, and stir-fry the beef for no more than 3 minutes. Remove the beef to a bowl, add 1 tablespoon of the tamarind water and toss to combine. In another bowl, combine the vegetable mixture, sawtooth coriander, Vietnamese mint, fried garlic and tamarind beef. Add the remaining 1 tablespoon of tamarind water and Nuoc Mam Dipping Fish Sauce. Toss the salad to combine all the ingredients. Garnish with the peanuts and chilli.
Combine the fish sauce, rice vinegar, sugar and 1/2 cup of water in a saucepan and place over medium heat. Stir well and cook until just before boiling point is reached, then remove from the heat and allow to cool. To serve, add the garlic and chilli, then stir in the lime juice. Store tightly sealed in a jar in the fridge, for up to 5 days. Yield: about 1 cup