Zest the lemon into a large bowl using a fine grater. Cut the lemon in half and squeeze in the juice from one half. Add in the extra virgin olive oil and season with sea salt and freshly ground black pepper. Mix well.
Put a pan of salted water on to boil. Once boiling, steam or boil your beans until tender. Drain well, then tip the cooked beans into the bowl with your dressing and toss everything together, making sure all the beans get coated. Have a taste and squeeze over the remaining lemon juice if you think it needs it, then serve.
Jamie's top tips
Dressing vegetables while warm helps them absorb some of the dressing, which means less dressing is needed to season.
This very simple dressing can be used for all kinds of veggies. Use this recipe to learn how to balance the oil and acidity in a simple dressing.
The beans can be served hot, warm or at room temperature, but if they sit in the dressing too long, they will start to discolour so either eat them straightaway or dress them just before you want to eat them.