Rub the steak pieces in salt. Put them in a bowl, pour in the buttermilk, cover with clingfilm and allow to chill overnight.
For the salad, dice the cucumber and apple into pieces of a similar size. Dress with balsamic vinegar, olive oil and a pinch of salt. We recommend doing this in advance, so the vinegar has time to wilt the salad a little.
Mix the mustard, salt, yolk, paprika, water and vinegar with a whisk in a round-bottomed bowl. Pour in the oil slowly, whisking vigorously until the mayonnaise thickens. Do not be tempted to add the oil too quickly or the mixture will split.
When your garnish is ready, preheat the fryer to 170°C.
Prepare the flour coating by mixing all the dry ingredients. Pick the steak pieces out of the buttermilk and dip them in the flour on a shallow plate.
Allow each piece to sit in the flour for a minute so that it soaks in and sticks to the buttermilk that is left on the meat.
Carefully place the pieces in the deep fat fryer and allow to fry for 4-5 minutes.
When they are ready, remove the steak pieces from the fryer and place on a piece of paper towel to drain off excess oil before serving.
Enjoy!