3 Tbs Olive oil, divided, plus more for brushing
4 cups thinly sliced onions
3 large garlic cloves, chopped
1 Tbs chopped fresh thyme
1 tsp chopped fresh rosemary
2 lbs Yukon Gold potatoes, peeled, sliced into 1/8 in-thick-rounds
3/4 tsp coarsely ground black pepper
1&1/4 cups low-salt chicken (I use vegetable) broth.
Heat 2 Tbs oil in large skillet over medium-high heat. Add onions and garlic; sprinkle with salt and pepper. Saute until onions are golden, about 8 mins. Add thyme and rosemary; saute 2 mins. DO AHEAD: Can be made 2 hous ahead let stand at room temp.
Prehead oven to 425 F. Brush 11x7x2-inch glass baking dish with oil. Arrange 1/3 of potatoes in dish. Sprinkle with 1/4 tsp each salt and pepper. Top potatoes with half of onion mixture. Repeat, top with potatoes. Pour broth over. Drizzle with 1 Tbs oil.
Cover dish with foil. Bake potatoes 30 mins. Uncover and continue to bake until potatoes are tender and top is golden, about 25 mins longer. Let stand 10 mins and serve.
*If you don't have fresh herbs you can still use dried, just don't use as much (dried is stronger than fresh.)
We had a Cesar salad, the potato-onion gratin, peas&corn and garlic bread.