To prepare the prawn filling: dab the prawns dry with kitchen paper. Next, either by hand or in a food processor, finely chop or blitz the prawns until they become almost paste-like.
Scoop into a large mixing bowl and add the garlic, sugar, cornflour, sesame oil and egg white. Season with salt and freshly ground black pepper pepper. Mix well to combine.
To make the prawn toasts: lay one piece of crustless white bread on a board. Spread with some (about ¼) of the prawn mix, then top with another piece of bread. Press down firmly to create a sandwich. Repeat with the other slices so you have 4 sandwiches.
In a shallow bowl (wide enough to dunk each sandwich one at a time), whisk together the egg and egg yolk until combined. In another shallow bowl, add the sesame seeds.
One at a time, dunk each sandwich into the egg mixture, turning to coat both sides. Then place in the sesame seed mixture and repeat, making sure you get a good, even coating. Try to keep one hand for the ‘wet’ (e.g. the egg mixture) and one hand for the ‘dry’ (e.g. the sesame seeds).
To fry the sesame prawn toast: line a large baking sheet with kitchen paper and set aside. Pour in enough oil to come 2-3 cm up the sides of a large, deep frying pan. Place over a medium-high heat until shimmering hot, but not smoking - if you have a thermometer, it should be 180C. You can test to see if it is hot enough by dropping a small piece of bread (or leftover crust) into the oil - if it floats and starts to sizzle then you are at the right temperature.
While the oil is heating up, make the green sauce (if using): put all the ingredients into a blender or mini food processor and blitz until smooth. Taste and adjust the flavours, adding more chilli (to make it spicier), lime juice (for tartness) or water (to loosen). Pour into a bowl and set aside.
Once the oil is at the right temperature, carefully add around two of the sandwiches. It will depend on how big your sandwiches are and your pan too. Do not overcrowd the pan as the temperature will drop and that’s how you get soggy prawn toast! Fry for 1-2 minutes. Using a spatula, gently turn over, then cook for another 1 minute - or until golden brown and crispy on both sides and the prawn paste is cooked through. Remove from the pan and place onto the prepared baking sheet to drain off any excess oil. Repeat with the remaining sandwiches.
Slice the sandwiches in half to create 8 triangles and place onto a plate (you can cut into 16 smaller ones, if you prefer). Drizzle with the green sauce and garnish with shallot rings and freshly chopped coriander, parsley or chives. Enjoy with sweet chilli sauce or a spicy sriracha yoghurt or mayonnaise on the side, if you like.
The video below will help with this reciope.