Indian cumin and mint cooler (Jaljeera)

1. Dry-roast the cumin seeds in a frying pan for 1-2 minutes until fragrant and lightly browned, then grind finely in a mortar.

2. Pick the mint leaves off the stalks (setting a few aside for garnish), and peel and roughly chop the ginger.

3. Blend the mint, ginger, roasted cumin, amchur, black salt, sugar and lemon juice with 200 ml water until completely smooth.

4. Strain through a fine sieve into a jug, pressing the fibres left in the sieve firmly with a spoon.

5. Top up with the rest of the cold water, stir and taste: it should be tangy, salty and refreshing all at once; adjust with a little lemon juice or black salt if needed.

6. Pour into glasses filled with ice, garnish with a mint leaf and sprinkle a pinch of roasted cumin on top. Serve cold.

Tip: Jaljeera means "cumin water": in North India it is served as an appetiser and digestive drink on hot summer days. If you can't get amchur (dried green mango powder), a little extra lemon juice or tamarind paste can stand in for the sourness.