01 - Combine dark rum and brown sugar in a shallow dish. Add pineapple pieces, turning to coat evenly. Let soak for 10–15 minutes, flipping halfway through to ensure full 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 temperature reaches 350°F.
04 - Remove pineapple from the rum mixture and pat lightly dry with paper towels to remove excess liquid. 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 and ensure even cooking.
06 - Transfer fried pineapple to a paper towel-lined plate to drain excess oil. Serve warm, drizzled with honey or maple syrup, sprinkled with cinnamon, and accompanied by vanilla ice cream or whipped cream if desired.