Corned Beef Hash

Preheat oven to 350°F. Pierce potatoes with fork; wrap in foil. Bake potatoes until tender, about 1 hour. Cool. Peel and cut into 1-inch cubes.

Heat bacon fat in heavy large skillet over medium-high heat. Add onions and cook until tender, stirring occasionally, about 15 minutes. Add carrots and cook until onions caramelize and carrots are tender, stirring often, about 15 minutes. Season to taste with salt and pepper. Transfer to bowl. Mix in potatoes, thyme, corned beef, and corned beef fat. Season to taste with salt and pepper. Partially mash with potato masher (mixture will begin to clump together). Shape hash into ten 1-inch-thick patties, using 3/4 cup hash for each. Place on baking sheet. Cover and chill until cold, about 2 hours. DO AHEAD Can be made 1 day ahead. Keep refrigerated.

Heat 1 tablespoon oil in heavy large nonstick skillet over medium-high heat. Working in batches, add hash patties and cook until crisp and brown, adding more oil to skillet as necessary, about 4 minutes per side. Transfer to plates.