700g green beans
4 tablespoons oil
1 small onion, diced
2 tablespoons tomato puree
1 chicken stock cube, chopped
Lemon juice (optional)

String cut, wash and drain the beans. Heat the oil in a pressure-cooker and fry the onion gently.

Stir in tomato puree, dissolved in 3/4 glasses of water. Add lemon juice, if using, and the chicken stock cube. Add the beans, stir for 3-4 seconds and pour in sufficient water to nearly cover them.

Cover and remove from heat 1-2 minutes after the pressure valve rises (whistles). The cooking time depends on the type of the pressure-cooker. Uncover and, if it is necessary, reheat again on high heat until the sauce thickens.