Mary Berry makes a tasty vegetable dish with her fennel and potato gratin on this week’s episode of Mary Berry cooks.

Mary says: “This is the perfect combination of potatoes and vegetables all cooked in one dish for a hearty dinner party or Sunday lunch. It is so tasty I could eat it as a supper on its own!

The ingredients are: 50g butter, 3 large bulbs fennel, 3 onions, 600g large potatoes, 2 garlic cloves and 50g parmesan cheese.

To prepare the fennel and potato gratin: trim the tops from the fennel and cut each bulb in half through the root, then cut each half lengthways into three wedges. Cut the onions into six wedges too in a similar way.

Cut the potatoes into wedges the same size as the fennel wedges.

Boil the fennel and onions in a large pan of salted water for about five minutes, then add the potatoes and boil for a further five minutes, or until the potatoes and fennel are just tender. Drain well.

Put the 50g butter and the garlic in the same large pan set over a low heat until just melted. Return the potatoes and fennel to the butter, toss until coated then tip into the ovenproof dish. Sprinkle with the parmesan.

Bake in a preheated oven at 200C for 30-40 minutes, or until piping hot.