Place prawns, egg white, wine, cornflour, garlic, ginger, sesame oil, oyster sauce, sugar, white pepper & salt into a small food processor or blender and blend until a smooth paste forms. Transfer mixture to a bowl. Stir through spring onions and coriander, if using. Cover and chill for 30 minutes.
Lay bread slices out on a clean work surface. Roughly divide prawn mixture into 6. Top each slice of bread with one portion of the mixture. Using a spatula or butter knife, spread the prawn mixture evenly over the bread and going right to the edges. Repeat with all slices of bread.
Pour enough cooking oil into a large frying pan to come 2-3cm up side of the pan. Heat over medium-high heat until oil reaches 180C (when oil is ready, a cube of bread turns golden in 15 secs). Cook the bread, in batches, prawn-side down, for 5 mins or until sesame seeds are golden and prawn mixture is cooked through. Turn and cook for 1-2 minutes or until golden underneath. Transfer to a plate lined with paper towel then to a wire rack.
Pour enough cooking oil into a large frying pan to come 3cm up side of the pan. Heat over medium-high heat until oil reaches 180°C (when oil is ready, a cube of bread turns golden in 15 secs). Cook the bread, in batches, prawn-side down, for 5 mins or until sesame seeds are golden and prawn mixture is cooked through. Turn and cook for 1-2 minutes or until golden underneath. Transfer to a plate lined with paper towel then to a wire rack.
To serve, cut each slice of prawn toast into quarters (24 pieces) or in half (12 pieces) for bigger portions. Transfer to a serving plate and garnish with coriander sprigs and spring green onions (yes, I forgot to put them on for the photo - silly me ☹️) Serve with Sweet & Sour Sauce, sweet chilli, soy, Sriracha or Kewpie mayonnaise.