Heat the oil in a deep frying
pan and cook the onion for
about 5 mins until soft. Add the
chipotle paste, beans, tomatoes
and sugar, and simmer for about
15-20 mins until thickened.
Season to taste.
Make 4 holes and crack an egg
into each one. Cover and simmer
over a low heat for 8-10 mins until
the eggs are cooked to your liking.
Sprinkle with coriander leaves and
serve with a bowl of soured cream
and some warm flour tortillas.