Prepare the Mushrooms: Wash and pat dry the mushrooms. Trim the stems if necessary, but keep them intact for easy dipping.
Make the Batter: In a bowl, mix flour, cornstarch, baking powder, paprika, cayenne, garlic powder, salt, and black pepper. Slowly whisk in the ice-cold sparkling water until the batter is smooth and slightly thick.
Heat the Oil: In a deep pan, heat vegetable oil to 180°C (350°F). Test with a drop of batter—it should sizzle and float.
Coat and Fry: Dip mushrooms in the batter, allowing excess to drip off. Fry in small batches until golden brown, about 2-3 minutes per batch. Remove with a slotted spoon and place on paper towels to drain.
Prepare the Sauce: Mix soy sauce, rice vinegar, honey, chili flakes, sesame oil, and minced garlic in a small bowl.
Serve: Arrange the mushrooms on a platter with the dipping sauce on the side. Garnish with chopped parsley or sesame seeds for extra flair.
Notes
Keep the batter cold by placing it over a bowl of ice.
If you prefer less spice, reduce cayenne and paprika.