Pot-cooked black beans (Frijoles de olla)

1. Pick over the dried black beans, rinse and soak overnight in plenty of cold water; drain the next day.

2. Put the beans in a large (ideally clay) pot with the halved onion and the whole garlic cloves and cover with the fresh water.

3. Bring to the boil, skim, then simmer over low heat, covered with the lid slightly ajar, for 1½-2 hours until the beans are completely soft and creamy. If the water reduces a lot, top up with hot water – not cold, which toughens the beans.

4. Salt only in the last 20 minutes and add the epazote at that point too. If you have no epazote, a bay leaf also gives a nice aroma.

5. Remove the onion and serve the beans with their thick broth in small bowls.

6. Serve with fresh coriander, chopped onion, serrano and crumbled cheese, with warm tortillas.

Tip: If you salt too early, the bean skins stay tough – so the salt always goes in at the very end.