Egg gratin with mashed potatoes

To make a delicious Anglesey egg gratin with mashed potatoes, the first thing you need to do is peel and wash the potatoes, and cut them into medium-sized cubes.
We cook in a saucepan with water, over medium heat, for 20 minutes, until tender. Then drain them and add the cream and half of the butter.

Put the leeks in a saucepan and add water, and cook for 10 minutes, until tender. Set aside in a bowl.
The eggs are cooked in another tray with salted water over medium heat for 10 days, then rinsed with cold water and allowed to cool.