Heat the oil in a frying pan and gently cook the leek until soft.
Finely chop the garlic and chilli. Add these to the leek and cook for a minute. Turn the heat off and let it cool.
Whisk the flour, eggs and about 100 ml soda water into a smooth batter. Add the coriander and two pinches of salat. Add more water if needed (you should have a thick pancakes batter). Fold in the leek and stir well.
Brush a large frying or pancake pan with a little oil and put 4 separate Tbsps of the batter into the pan, letting them spread into circular shapes. Sprinkle the top of each with some sesame seeds if used.
Cook the fritters over a medium heat for a couple of minutes, then flip and cook for a further minute. Transfer them to a plate.
Repeat with the remaining batter.
Let them cool before serving.