Whisk together flour, cornstarch, and salt in a bowl.

Create a well in the center of the dry ingredients.

In a separate bowl, combine ice water (or beer) and egg yolk, whisking until frothy.

Pour the wet ingredients into the well of the dry ingredients.

Gently stir the mixture until just moistened, leaving some lumps.

Fold in the stiffly beaten egg whites.

Use the batter immediately.

Heat oil or shortening in a deep fryer or large pot to 400°F (200°C).

Dip fish, shrimp, or vegetables into the batter, swirling to ensure even coating.

Carefully place a few pieces at a time into the hot oil.

Fry for 2-3 minutes, or until golden brown and cooked through.

Remove the fried items and drain on paper towels.

Ensure vegetables are thoroughly dry before dipping for optimal batter adhesion.