Green chili and lime prawns (Aguachile verde)

1. Use only very fresh prawns suitable for eating raw. Peel the prawns, slit the backs to remove the dark vein and butterfly them lengthwise; put them in an ice-cold bowl and salt them.

2. Squeeze the limes and blend the juice with the serrano chilies, half the coriander, the water and a pinch of salt until smooth and bright green.

3. Pour the green liquid over the prawns and marinate in the fridge for 10-15 minutes, until the prawns turn slightly white and opaque – no longer, or they get rubbery.

4. Meanwhile, peel the cucumber and cut into thin half-moons, slice the red onion hair-thin and slice the avocado.

5. Arrange the prawns on a flat plate with the cucumber and onion, pour over the green liquid and garnish with avocado and the rest of the coriander.

6. Serve immediately, ice-cold, with tostadas or tortilla chips.

Tip: If you don't want them raw, blanch the prawns for 1 minute first and cool in iced water – the flavour stays just as fresh.