Instructions

1. Thinly slice the leek.
2. Heat the oil in a pan and gently sauté the leek until soft.
3. Add the beans and stock, then bring to the boil.
4. Cook for 5 minutes under cover, then turn up the heat and reduce the sauce by half.
5. Add the lemon juice and zest, then turn off the heat.
6. Season to taste, then fold in the rocket leaves.
7. Serve warm.