Mashed Potato Gratin with Carmelized Onions

Last night was the second gathering of our new Supper Club and it was quite a turnout. I don’t know about all of you but I had a blast! Ian and I wanted to pick something simple that everyone would like, so we went with the same menu as his Birthday dinner... RIBS! On Saturday I went to the Maitre Boucher and picked up 10 POUNDS of ribs, then proceeded to cook them all in my tiny oven.

Even though ribs were the star of the show, many people couldn’t get enough of the supporting actor, the mashed potato gratin with caramelized onions. Basically this dish is made from Ian’s delicious mashed potatoes with a generous layer of caramelized onions in the middle and topped with grated 2 year old port soaked cheddar.

This mashed potato recipe has been a winner since the first time I made it, and whenever my mom or I have to bring a side dish to a party, we make this. Plus it is so easy and can be made well in advance. For years people have been asking for the recipe so here it is guys, use it wisely! Usually I make them with grated Asiago on top instead of the cheddar which gives a great punch but some people don’t like strong cheese so old cheddar is a great alternative.

Ian and I just wanted to thank all of you for a great night, and especially Kelly who made a killer beer and caraway seed bread and her little darling two year old Mason, who tuckered himself out making butter from whipping cream for the bread. Also, big thanks to Alex who brought a super decadent flourless chocolate cake and perfect apple pie. We couldn’t have done it without you guys!

Mashed Potato Gratin with Caramelized Onions
adapted from a really old LCBO magazine
this is my half recipe that serves 4-5 people

1 tbsp olive oil
3 cups sliced sweet onions
Salt and pepper
1 tbsp sherry vinegar
2/3 cup chicken or beef stock
Freshly ground pepper
1-1/2 lbs yellow fleshed potatoes, peeled and cut in even-sized chunks
10% cream or a couple spoonfuls of sour cream
2 tbsp butter
Salt and freshly ground pepper
½ cup grated Asiago or 2 year old cheddar cheese

Heat oil in a large pan over medium heat. Add onions and salt and sauté until onions start to soften. Add half a cup of water and continue to cook until the water has evaporated. Add a second half cup of water and repeat, stirring occasionally, until onions turn golden brown. Stir in vinegar and stock. Raise heat to high and reduce until stock almost completely disappears. Remove from heat, season with salt and pepper and reserve.
While onions are cooking, place potatoes in boiling water to cover and bring to boil until potatoes are tender. Drain well and mash potatoes with a potato masher while beating in enough cream to make a smooth mashed potato, and the butter. Season well with salt and pepper. Preheat oven to 350.In a large gratin dish layer a half of potatoes and the onions. Layer on the rest of the potatoes and sprinkle with cheese. Bake 20 to 25 minutes or until top is browned and potatoes are hot.