Green Mango Shake (Manggang Hilaw Slush)

Method

1. Choose firm unripe mango with pale flesh and a clean sour aroma, not spoiled fruit. Wash before peeling, cut flesh away from the hard stone and weigh the edible portion. Dice small enough for your blender, removing any tough fibres near the seed.
2. Combine sugar and the syrup water in a small pan. Heat just until dissolved, simmer for 1 minute and remove from the heat. Cool completely before using; hot syrup would melt the ice and change the intended texture.
3. Put mango, cold blending water and about two-thirds of the cooled syrup in the blender. Blend until the fruit is finely puréed, stopping to scrape down with the machine switched off if necessary.
4. Add the ice in two additions and pulse, then blend until evenly slushy. Only use a blender rated for crushing ice. Do not force frozen cubes into a small stick-blender cup that is not designed for them.
5. Taste a small spoonful and add the remaining syrup gradually if required. Green mango acidity varies substantially. Add the optional tiny pinch of salt only to round the flavour, not enough to make a salty drink.
6. If too thick to pour, add cold water a tablespoon at a time. If too thin, add a few more ice cubes and blend briefly. Serve straight away in two chilled glasses before the ice separates from the fruit.
7. For preparation ahead, refrigerate the mango purée and syrup separately for up to 1 day and blend with ice only when serving. A finished slush loses its texture in storage; do not leave it sitting at room temperature for a later service.