01 - Combine dark rum and brown sugar in a shallow dish. Add pineapple pieces, turning to coat thoroughly. Let soak for 10–15 minutes, flipping halfway through to ensure even absorption.
02 - Whisk together flour, cornstarch, and salt in a medium bowl until well combined. Gradually whisk in cold sparkling water until a smooth, thick batter forms without lumps.
03 - Pour 1 inch of vegetable oil into a large skillet or deep pan. Heat over medium-high heat until oil reaches 350°F.
04 - Remove pineapple from the rum mixture and pat lightly dry with paper towels. Dip each piece into the batter, allowing excess to drip off for even coating.
05 - Fry pineapple pieces in batches for 2–3 minutes per side until golden brown and crispy. Avoid overcrowding the pan to maintain proper oil temperature.
06 - Transfer fried pineapple to a paper towel-lined plate to drain excess oil. Serve warm with optional honey or maple syrup, cinnamon sprinkle, and vanilla ice cream or whipped cream.