Add the green beans to a medium pan and cover with water. Simmer for 3-4 minutes until just tender, then drain all the water from the pan.
Step 2
Add the butter to the pan with the green beans. Thinly slice the radishes and add to the pan along with the lemon zest, salt and pepper. Stir well and saute gently for 3-4 minutes until the vegetables are tender.