Spread coconut evenly over a buttered baking tray.
In a medium microwave-safe bowl, combine sugar and golden syrup. Microwave on high 3 minutes. Stir in nuts and microwave 4 minutes more. Stir in butter and vanilla and return to microwave for 1 minute. Stir in bicarb soda until light and slightly foamy. Pour over coconut in tray. Let cool until firm, 1 hour. Break into pieces.