Butternut and leek gratin
Up your gratin game with delicious, tender layers of butternut, leek and sage.
I’ll often roast a chicken by sitting it in a bed of butternut pumpkin and leeks. Once the chicken’s done, I’ll take it out to have its rest, crank the oven up and put the tin of vegetables back in for a few more minutes to crisp up.
This gratin is another, more interesting way with the same vegetables. It’s more likely to appear on my table on one of those weekends when I'm feeling expansively domestic, happy to put the time into slow-roasting a chicken – here’s my four-hour method – and want cozy side dishes to go with it. It helps that the gratin can go into the oven as the chicken comes out, and is ready to eat by the time the chicken’s been rested and carved.
Because leeks come in different sizes, I’ve specified a weight, using the white and pale green parts only. Grit is often trapped between the layers of a leek – they’re mounded with soil once they emerge from the ground – so I suggest slicing them before giving them a rinse in a colander.
Butternut and leek gratin
Serves 2–4, as a side dish.
100g (4 oz) leek
1 tablespoon butter
1 tablespoon finely chopped sage
800g (1¾ pounds) butternut pumpkin
6 tablespoons finely grated Parmesan
80ml (⅓ cup) cream
sea salt flakes
freshly ground black pepper
butter, to prepare the dish
Cut the leek in half lengthways and cut into thin slices. Place in a colander and rinse under cold running water, draining well.
Melt the butter in a frying pan over medium heat. Add the leeks and 2 teaspoons of the sage. Season lightly with salt and pepper. Cook, stirring occasionally, until the leek is soft. Set aside.
Set your oven to 200°C (400°F) and butter a 3-cup capacity baking dish.
Peel the butternut pumpkin, remove any seeds with a spoon, cut it in half and slice thinly. A mandoline is useful here.
Layer half the butternut slices in the dish, season lightly, and sprinkle with 2 tablespoons of Parmesan. Spread the cooked leeks over, topping with another 2 tablespoons of Parmesan. Cover with a layer of the remaining butternut.
Pour the cream over, season with a little salt and pepper, then sprinkle with the remaining cheese and sage.
Bake for about 30 minutes, until the butternut is tender and the top develops some nice colour.
