Potato Gratin With Caramelized Onions - cooking recipe

Ingredients

2 cups whipping cream (I used 2%milk)
4 cloves garlic, slivered
3 peppercorns
2 sprigs fresh thyme
3/4 teaspoon salt
1 tablespoon vegetable oil
1 Spanish onions or 2 onions, finely sliced
3 large yukon gold potatoes, about 2 1/2 lbs
1/2 cup shredded gruyere cheese

Preparation

In saucepan, bring cream, garlic, peppercorns, thyme and salt to boil, reduce heat to low, cover and simmer for 15 minutes.
Remove from heat and set aside.
Meanwhile, in nonstick frypan, heat oil over medium low heat; cook onion, stirring often, until light brown, about 45 minutes.
Slice potatoes as thinly as possible, use mandoline if available.
Layer one quarter of the potatoes in greased 8 inch square glass baking or casserole dish; top with one third of the onion and one quarter of the cheese.
Repeat twice.
Top with remaining potatoes.
Strain cream mixture over potatoes, shaking casserole to distribute evenly; sprinkle with remaining cheese.
Bake at 300f degree oven until tender and knife inserted in bottom pierces potatoes easily, 1 1/2 to 2 hours.
(Make ahead: let cool; cover and refrigerate for up to 2 days. Reheat in 375f degree oven for 30 minutes.).