Leek and Potato Gratin

Introduction & method

This delicious potato and leek gratin is perfect either as a vegetarian main course or as a side dish. If you're bored of mash, chips or roasties, have a go at this.

Prep the Leek

Trim the outer leaf of the leek, tidy up the top and bottom and thinly slice it. Melt together some oil and butter in a frying pan and sauté the leek on medium heat for about 5 minutes - you want to soften it but don't brown it. Add the minced garlic for the last minute. Set aside and allow to cool.

Prep the Potatoes

Peel and thinly slice the potatoes - they need to be 3-4mm (just under a quarter of an inch). A mandolin is the best thing to achieve even slices. Bring a pan of salted water to the boil and pop the potatoes in for 5 minutes. Remove, drain and allow to cool.

Assemble and Bake the Gratin

Heat the oven to 160°C (fan), 180°C (conventional), gas 4. Grease the inside of a casserole dish with butter. Spread a layer of potatoes in the bottom (about one-third of the slices), overlapping them slightly so there's a bit of air underneath them. Season with salt and pepper. Mix the leeks with the milk and cream and pour half of the leeks over the potatoes. Arrange a second layer of potatoes over this, then season it and spread the remaining leeks (but not the liquid) over it. Arrange the final third of the potatoes on top, pour the last of the milk/cream over it, and cover with a layer of grated cheese. Put a lid on the casserole and bake for 20 minutes, then remove the lid and cook for another 20-30 minutes until the cheese is golden brown and the potatoes are tender.