Find More Recipes

Sweet Onion and Potato Gratin

Ready in 35 mins

Recipe by Graham 

What can I say? ... Sweet Onion and Potato Gratin - the comfort food of the gods. Perfect dish to accompany just about any grilled meat, particularly Grilled Gammon Steak or Grilled Chicken Portions. It's particularly nice with something simple and straightforward like Baked Sausages

Preparation Time

5 Minutes

Cooking Time

30 Minutes

Ingredients for Sweet Onion and Potato Gratin

If you are not familiar with any ingredients, please check our International Cooking Terms page.

Currently displaying quantities in US Imperial Measurements

To serve 4:

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

PLEASE NOTE: This recipe calls for the GRILLING or BROILING of food. In most countries of the world, the term "grilling" refers to heat coming from above the food source. Significantly, in North America, it signifies heat from below the food (such as barbecuing). In the United States and Canada, when the heat source for grilling comes from above, grilling is termed broiling, and the pan that holds the food is usually called a broiler pan.


How to Cook Sweet Onion and Potato Gratin

  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.
GRAHAM'S HOT TIP:
Red onions are best for this dish. The taste is very similar but the appearance is enhanced by the red tinge.