Soak gelatine leaves in cold water for 15 minutes (or 5 for the quick-dissolving variety).
Heat 150ml (5fl oz) of the pressé until just simmering in a pan. Remove the gelatine leaves from the water, squeeze off excess liquid, then whisk into the hot pressé. Whisk in the remaining pressé. Pour into a bowl, cool and refrigerate overnight or until fully set.
Prop up some papaya slivers in tumbler glasses. Run a sharp knife through the jelly to break it up. Spoon into glasses with the papaya, and top with a splash of pressé before serving.