Guacamole

1. Very finely chop a quarter of the red onion, the serrano and half the coriander and grind them to a paste with a pinch of salt in a mortar (or in a bowl with a fork) – that's where the flavour comes from.

2. Halve and stone the avocados and scoop the flesh into the mortar with a spoon.

3. Mash roughly with a fork – it shouldn't be completely smooth; leave some small chunks.

4. Squeeze in the lime juice and add the rest of the finely chopped onion and coriander.

5. Deseed and finely dice the tomato, fold it in gently and season with salt to taste.

6. Serve immediately with tortilla chips or with tacos.

Tip: If you're not eating it right away, smooth the top and cover with cling film pressed directly onto the surface – that way it won't turn brown.