"This is a robust warming gratin made with one of my favourite winter vegetables, the cheap and cheerful swede turnip" says Rory O'Connell.

Ingredients

Swede turnips need to be peeled before use. If the greens are attached, they too are edible and can be de-stalked, cooked and folded through the cooked root to give a really lovely earthy flavour.

When buying, pick one that feels heavy for its size with an unblemished skin. Turnips will store for you in a cool place for several weeks.

The smoked bacon should be from the belly and be quite fatty to ensure a succulent texture and a sweet flavour. The lardons are little strips or cubes cut not less than half of 1 cm thick.

  • 450g swede turnip, peeled and sliced into 4 mm slices
  • 450g potatoes, peeled and sliced into 3 mm thick slices 
  • 110 g lardons of smoked or unsmoked bacon
  • 1 tablespoon olive oil
  • 110 g grated parmesan
  • 1 teaspoon thyme leaves
  • 350ml cream or chicken stock
  • salt and freshly ground black pepper
  • 1 x 1.5 l ovenproof gratin dish

Method

  1. Preheat the oven to 180c / 350f / gas 4.
  2. Bring a large saucepan of water to the boil and season with a good pinch of salt.
  3. Drop in the sliced turnips, bring back to the boil and simmer for 5 minutes. The turnips will have tenderized slightly but will not be fully cooked. Strain out the turnips, reserving the water for cooking the potatoes. Place the turnips on a tray lined with a tea towel.
  4. Bring the water back to the boil and add the sliced potatoes. Bring to a simmer and cook for 1 minute only. Strain and rinse under the cold tap and place on a tray lined with a tea towel like the turnips. 
  5. Heat the 1 tablespoon of olive oil in a frying pan and add the bacon lardons. Cook stirring until the bacon is crisp and golden. Strain out the bacon and place on a piece of kitchen paper towel to drain. 
  6. To assemble the gratin, grease a 1.5 litre gratin dish with a light smear of butter. Place on a layer of the turnips and potatoes, followed by a sprinkle of thyme leaves, a sprinkle of lardons of bacon and a sprinkle of the grated parmesan.
  7. Season with salt and pepper. Splash on a little of the cream. Repeat the process finishing the gratin with a final sprinkle of the cheese.
  8. Place the gratin in a bain marie in the preheated oven and cook for 60-80 minutes. After 60 minutes, test the gratin with a skewer to see if the potatoes and turnips are tender. The skewer should go through the vegetables with no resistance and the top of the gratin should be a rich golden colour.
  9. The cooked gratin will sit happily in the oven for an hour before serving with the temperature reduced to 50c / 120f / gas ¼ .