01 - If using fresh pineapple, peel, core, and slice into 1/2-inch rings. Pat dry thoroughly with paper towels to remove excess moisture.
02 - In a medium bowl, whisk together flour, cornstarch, sugar, baking powder, and salt. Stir in cold sparkling water and egg (if using) until just combined. Do not overmix—small lumps are acceptable.
03 - In a deep skillet or saucepan, heat vegetable oil to 350°F. Maintain temperature throughout frying for consistent results.
04 - Dip each pineapple ring into batter, turning to coat completely. Allow excess batter to drip off before frying.
05 - Carefully place battered rings in hot oil, working in batches to avoid overcrowding. Fry 1–2 minutes per side until golden brown and crispy. Remove with slotted spoon and drain on paper towels.
06 - Dust generously with powdered sugar and sprinkle with cinnamon if desired. Serve immediately while warm, optionally accompanied by vanilla ice cream or caramel sauce.