Cut the fish into strips of about ¾” (2 cm). In a bowl, season the fish with salt, pepper, and mustard. Add the egg and mix well. Let rest for about 15 Minutes.
Place the white flour, corn starch and 1 tsp of salt in a separate bowl. Mix well.
Dredge the fish strips in the flour and shake to remove excess.
On the Instant Vortex control panel, press Air Fry, then set time to 13 Minutes and temperature to 400°F (205°C). Press Start.
Once Add Food appears on the display, add the fish, spraying it evenly with oil or drizzling 1 tbsp olive oi evenly over it.
Meanwhile, prepare the sauce. Place 1 raw egg in a blender, start blending and slowly pour in oil until mayonnaise consistency is obtained. Add salt, pepper, juice of half a lemon, 1 tsp mustard. Blend using blender. Place the mayonnaise in a container; add grated hard-boiled egg, diced onion, and Chinese onion. Mix and set aside.
Once 9 Minutes appears on the display, open the air fryer and check that there are no areas of the fish with dry flour; if so, spray them with a little oil.
Once Turn Food appears on the display, turn the fish over. Let cook for remaining time until screen says End.
Once the fish is ready, let cool for a few minutes and serve with the tartar sauce and fried cassava.