Potato, onion, sage and gruyère tart

Do put the time into caramelising the onions in this easy vegetable tart – the natural sweetness sets off the gruyère and sage beautifully.

Ingredients

• 4 tbsp olive oil
• 6 sage leaves
• 3 onions, peeled and finely sliced
• 250g/9oz ready-rolled all-butter puff pastry
• 3 large cooked leftover roast potatoes (or boiled potatoes), quartered
• 150g/5½oz gruyère (or alternative vegetarian alpine cheese)

Method

1. Preheat the oven to 190C/170C Fan/Gas 5.

2. Put the olive oil and sage leaves in a pan. Fry until crisp and then immediately remove the sage leaves and set aside.

3. Add the sliced onions to the same pan. Cook over a low to moderate heat for 20-30 minutes, stirring occasionally, until soft and caramelised. Set aside.

4. Lay the puff pastry out on a lined baking tray and top with the caramelised onions, leaving a border all around. Top with the potatoes and grated gruyère. Bake for 20-25 minutes.

5. Remove from the oven when golden-brown, garnish with the crisp sage leaves and serve.

Potato, onion, sage and gruyère tart