Sift dry ingredients, corn flour, 2 tablespoons cornstarch, baking soda, baking powder, onion powder, garlic powder, paprika, into a bowl.
Add sugar and salt. Mix well.
Slowly add beer, sparkling water, club soda or water and mix well to make a batter. Set aside.
Add 1 cup cornstarch into a second bowl. Set aside.
Fill a pan or skillet with about 1 inch of oil.
Heat to medium high heat on the stove.
When oil is hot, place piece of fish into cornstarch. Flip and roll around, pressing slightly, to coat fully and evenly.
Immediately dip in batter. Cover completely.
Move fish over oil and allow excess batter to dip into oil to create the "krums" as you very carefully lower fish into oil.
Repeat with 1 or 2 more pieces of fish. Do not crowd the pan.
Fry krums and fish to a nice golden brown. Krums will finish first, the fish should take about 5 minutes.
With a spider strainer, remove the krums as finish and then the fish to a paper towel-covered plate or wire rack to drain.
Repeat until all fish filets are cooked.
If you like, drizzle the remaining batter into the hot oil to make more krums.
Serve with Malt Vinegar.