Rustic Potato, Yorkshire Blue and Walnut Tarts

• 2 tablespoons olive oil
• 1 onion, thinly sliced
• 1 teaspoon

Heat the olive oil in a pan, add the onion and thyme and cook for 8-10 minutes until the onion is lightly coloured. Cook the potatoes in boiling salted water for 5-8 minutes, until just tender, then drain in a colander.

Put the onion, fresh thyme, potatoes, chives, cheese, walnuts and crème fraîche in a bowl and season to taste. Place in the refrigerator until needed.