Put the beef in the freezer for around 1Â½ hours until it is about 70% frozen.
For the marinade, mix all the ingredients together in a large bowl with 50ml/2fl oz water.
Using a sharp knife, cut the partially frozen beef into 7cmx5mm/2Â¾xâ…›in batons. Add the beef batons to the marinade, cover and leave to marinate in the fridge for 2 hours.
For the pickled carrot, place the carrot in a sterilized airtight container. Heat up all the remaining ingredients in a non-reactive pan and bring to a gentle simmer. Pour over the carrot strips and leave to cool. Seal the container. (It will keep for several months if stored in a cool, dry place.)
For the Chinese five-spice salt, mix the powder and salt and combine thoroughly.
For the sauce, combine all the ingredients and 400ml/14fl oz water in a pan and cook until the mixture has reduced to the consistency of honey.
For the batter, combine the dry ingredients in a bowl, then whisk in enough sparkling water until you have a light batter
When the beef is ready, heat the vegetable oil in a deep-fat fryer to 180C. Alternatively, heat the oil in a deep, heavy-based frying pan until a breadcrumb sizzles and turns brown when dropped into it. (CAUTION: hot oil can be dangerous. Do not leave unattended.).
Remove the beef from the marinade, coat the beef in cornflour and plunge the batons individually into the batter before deep-frying until crispy (the fried batter coating should have miniature holes throughout instead of being a solid shell). Remove from the oil and drain on kitchen paper.
Add the beef to the sauce, season with a pinch of chilli flakes, Chinese five-spice salt and sesame seeds. Top with some pickled carrots, garnish with viola flowers, if using, and serve immediately.