Place the shrimp in a food processor (or use a knife) and pulse until finely minced.
Add the shrimp paste to a bowl and then add the egg white, cornstarch, soy sauce, sesame oil, grated ginger, garlic, sugar, and white pepper. Mix until smooth.
Fold in the chopped green onions.
Spread a generous layer of shrimp paste onto one slice of bread, making sure it's evenly covered.
Place another slice of bread on top to form a sandwich.
Optional: Add garlic powder to mayo for more flavor. Spread a thin layer of Japanese mayo on the outside of both sides of the sandwich.
Preheat your air fryer to 375°F (190°C).
Place the shrimp toast sandwiches into the air fryer basket in a single layer. Air fry for 8–10 minutes, flipping halfway through, until both sides are golden and crispy, and the shrimp filling is cooked through.
