Sweet Onion and Potato Gratin

Serves: to serve 4

Prep Time: 5 Minutes

Cook Time: 30 Minutes

Ready In: 35 mins

Ingredients

1 oz - butter

2 large - onions

  - salt and pepper

½ teaspoon - ground thyme

1 - bay leaf

2 lb - potatoes

1 oz - butter

up to ½ cup - milk

5 fl oz - double cream (heavy cream)

2 oz - Parmesan cheese

8 oz - Gruyere cheese

Directions

  1. Peel and thinly slice the onions. Melt the butter in a medium-size frying pan or skillet over low-medium heat. Add the onions and the bay leaf and season with salt the ground thyme. Cook gently for about 20 minutes until very soft and sweet and lightly caramelised. Season with salt and freshly-ground black pepper to taste, and discard the bay leaf.
  2. While the onions are cooking, peel the potatoes and cut into pieces of roughly equal size (A medium-sized potato is usually cut into about 6 pieces). Rinse the potatoes to remove any surface starch. Place them in a large pan with sufficient salted water to cover the potatoes. Bring the water to the boil then turn down the heat and cover the pan so that it continues to boil gently.
  3. Cooking time can vary depending upon the type of potato and the texture. Generally, however, somewhere between 15 - 20 minutes is sufficient. When you think that the potatoes are close to being cooked, pierce one or two of them with a fork. If the fork penetrates easily with little resistance, the potatoes are cooked.
  4. Remove the pan from the heat and drain off the water. Add the butter and, using a potato masher, begin to break up and mash the potatoes. Add milk until the texture is soft and light, then add the cream and Parmesan and season with salt and freshly-ground black pepper, to taste. Beat until the potatoes lift off on fairy wings all by themselves!!
  5. Preheat the grill (broiler) to high. Arrange the mashed potatoes in individual gratin dishes or one shallow casserole. Top the potatoes with the onions and then with grated (shredded) Gruyere cheese. Brown under a hot grill until bubbly, about 4-5 minutes. Remove from the grill and serve hot.