Instructions: Preheat the oven to 200C/400F/Gas 6.

Slice the potatoes lengthways to a thickness of about 1cm.

Trim the root ends of the onions taking care not to cut them off completely (you want the eventual slices to be held together by the root ends) and cut off the other ends.

Cut the onions in half vertically then into eighths.

The onions should be the same thickness as the potatoes.

Melt the butter in a large ovenproof dish or frying pan and add the onions and potatoes.

Fry shaking and turning so they become well coated with the butter and have taken on a little colour about 10-15 minutes.

Season with salt and pepper add the thyme and stir in half the balsamic vinegar.

Cover the pan with foil and bake in the preheated oven for 20 minutes.

Remove the foil and stir in the remaining balsamic.

Bake for another 20 30 minutes.

The potatoes should take on the colour of the vinegar and will become crisp as will the thyme.

Serves 6

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