Potato, Apple and Onion Gratin

Ingredients

• 0.3 cup breadcrumbs dried
• 1 tablespoon rosemary leaves fresh chopped
• 1.5 pound similar idaho potatoes sliced into ¼-inch rounds
• 3 teaspoon kosher salt divided
• 0.5 teaspoon freshly cracked pepper black
• 1 pound onions red peeled halved sliced
• 1 pound tart apples red cored peeled halved cut into ¼-inch-thick slices (such as granny smith, pippin, or pink lady)
• 6 tablespoon butter unsalted divided at room temperature

Equipment

• bowl
• frying pan
• baking paper
• oven
• baking pan
• aluminum foil

Directions

1. Preheat oven to 400 degrees F.Melt 3 tablespoons butter in large nonstick skillet over medium heat.
2. Add onions, rosemary, and 2 teaspoons salt; sauté until onions are tender and begin to carmelize, about 20 minutes.
3. Pour in water and wine to deglaze the pan.
4. Let the liquid come to a boil.
5. Remove from heat, let cool about 5 minutes.
6. Place the potatoes, apples, remaining 1 teaspoon salt, pepper and cooled onion mixture in a large bowl; toss gently to combine.
7. Transfer to 13 x 9 x 2-inch baking dish, spreading evenly. Cover dish with parchment paper, then cover with foil, shiny side down.
8. Bake gratin until potatoes are tender, about 45 minutes.
9. Remove from oven, uncover and dollop the remaining butter on top of the gratin.
10. Sprinkle with breadcrumbs.
11. Bake until top browns and juices bubble thickly, about 20 minutes longer. Can be made 6 hours ahead.
12. Let stand uncovered at room temperature. Rewarm, loosely covered with foil, in 300 degree F oven for 20 minutes.
13. Let gratin stand 15 minutes before serving.