01 - If using fresh pineapple, peel, core, and slice into 1/2-inch thick rings. Pat each ring thoroughly dry with paper towels to remove excess moisture, which helps the batter adhere properly during frying.
02 - In a medium mixing bowl, whisk together all-purpose flour, cornstarch, granulated sugar, baking powder, and salt until well combined. Gradually stir in the cold sparkling water and egg (if using) until just combined. The batter should remain slightly lumpy—avoid overmixing to prevent toughness.
03 - Pour vegetable oil into a deep skillet or heavy saucepan to a depth of 2 inches. Heat over medium-high heat until the temperature reaches 350°F. Use a kitchen thermometer for accuracy, as proper oil temperature ensures crispy results without excessive oil absorption.
04 - Working with one pineapple ring at a time, dip it into the batter, ensuring complete coverage. Lift and allow excess batter to drip off for a few seconds before frying. This step prevents an overly thick coating and promotes even cooking.
05 - Carefully lower the battered rings into the hot oil, working in batches to avoid overcrowding the pan. Fry for 1 to 2 minutes per side until deep golden brown and crispy. Use a slotted spoon to transfer fried rings to paper towels, allowing excess oil to drain.
06 - While still warm, generously dust the fried pineapple rings with powdered sugar. Add a light sprinkle of ground cinnamon if desired. Serve immediately as standalone treats, or accompany with vanilla ice cream or warm caramel sauce for an elevated dessert experience.