Squeeze the limes. Slice the pineapples into pieces and remove the peel. Save 4 pieces with peel as a garnish. Puree the pineapple with the lime juice until smooth. Halve the passion fruits and scoop out the flesh with a spoon.
Mix the passion fruit , sparkling water, tequila and Cointreau with the pineapple. Stir well or mix (in portions) in the cocktail shaker. Add some ice cubes to the glasses and pour over the margarita. Garnish with the reserved pineapple.
Prefer a mocktail? Replace the alcohol with 100 ml of good quality tonic.
