Steam the beans in a steamer or colander set over a saucepan of boiling water for 6 minutes or until crisp-tender.
Meanwhile, heat the oil in a large nonstick frying pan over moderately low heat.
Add the garlic and cook for 2 minutes or until soft. Add the stock, lemon zest, lemon juice and a pinch of salt, and bring to the boil.
Add the beans and cook for 2 minutes or until heated through and well coated. Add the dill, remove from the heat, and stir in the butter until melted.
Did you know?
Fresh beans offer useful vitamin C, folate, iron and – in the case of green beans – some beta-carotene. Although most people associate beta-carotene with orange vegetables and fruits, the chlorophyll in green vegetables can mask the orange colour. A surprising fact: green beans have more than five times as much beta-carotene as butter beans.