Mix shrimp, crabstick, onions, garlic, fish sauce, bread, basil, bell pepper and flour in a bowl. Add about half the egg. The mixture should not be too soggy, or it will be hard to form. If the mix is already wet enough, don’t add the remaining egg.
Mix and chill in the refrigerator for at least 30 minutes.
Prepare three separate bowls for the breadcrumbs, flour and egg (if the previous egg was not used completely, you could use that remaining egg here).
Take out the batter from the refrigerator. Using a spoon, scoop a small portion into your hands and shape it into a small ball. Press down lightly, so it forms into a patty shape.
Dredge this batter with flour, dip into the egg (make sure that the patty is completely covered) then coat with bread crumbs. Set aside.
Repeat the process for the remaining batter.
Heat oil in a pan. Deep fry patties.
Prepare the sauce. Mix the chilli sauce, mayonnaise, salt, black pepper and lemon zest. You c88an squeeze the lemon over the sauce a little bit to give a hint of lemon taste.