Combine passion fruit and pineapple juice and freeze. Place the frozen block in a colander lined with cloth and leave to drip till only colourless ice remains in the cloth (do not allow the block to melt completely).
Fill a shaker with some ice, gin and the dripped juice and shake to combine.
Muddle the Jalapeno at the bottom of a glass, then pour in the mixture and garnish with the mint sprigs. remove the Jalapeno before serving.