🥄 In a large bowl, combine flour, cornstarch, baking soda, baking powder, salt, and sugar. Mix well to distribute all the ingredients evenly.
Add Liquids:

💧 Add cold water and white vinegar to the dry ingredients. Whisk until the mixture is smooth and free of lumps. The batter should be thick enough to coat the back of a spoon but still liquid enough to drip off.

Rest the Batter:

⏲️ Let the batter sit for about 10 minutes. This rest time allows the baking powder and baking soda to start working, creating little air bubbles for extra crispiness.
Heat Oil:

🔥 While the batter rests, heat vegetable oil in a deep fryer or a deep pan to 375°F (190°C).