Finely chop the onion. Remove the vein from the peeled shrimp and chop them finely with a knife.
In a bowl, combine the mixture from step 1 and the seasonings. Mix well.
Cut off the crusts of the bread. Sprinkle potato starch on one side of the bread, spread the mixture from step 2 on top, then sprinkle Siscon Frost over the mixture and press it down lightly with your hand.
Heat oil in a frying pan over medium heat. Place the bread, frosted side down, into the pan and cook until golden brown. Then flip it over and cook the other side.
Note: The other side cooks faster, so be careful not to burn it. Be careful not to burn yourself while cooking or eating.