After much agonizing, I've come to think of this dish as a naked gratin and close cousin to pommes Anna. I used a mixture of rutabaga, kohlrabi and sunchokes (also called Jerusalem artichokes) in lieu of potatoes, and it was out of this world. The sunchokes, especially, gave it an amazing nutty earthiness. If you can find a pound or so of those, I highly recommend using them. But go with whatever root veggies suit your fancy. One other embellishment I loved … smoked sea salt. Not necessary by any means, but fun if you want to give it a little something extra.
14 cups very thinly sliced (use a mandolin) peeled (except for sunchokes) root vegetables (about 5-6 pounds)
3 tablespoons butter, melted
3 tablespoons oil, divided
Sea salt and freshly ground black pepper, to taste
1 tablespoon minced fresh rosemary
Smoked sea salt (optional)
Preheat oven to 400 F.
Toss the vegetables with the butter, 1 tablespoon oil, a generous pinch of salt and pepper, and rosemary. Use your hands to tease apart the slices and coat as many surfaces as you can.
Heat the remaining 2 tablespoons oil in a 10-inch cast-iron or ovenproof nonstick skillet over medium heat. When the oil is hot, swirl it around the pan and press a handful of vegetables flat onto the bottom of the pan. Repeat a handful at a time, stacking evenly to fill the pan and pressing them firmly into the bottom layers. Sprinkle with smoked sea salt, if you like, and give the pan a bit of a shake to settle all the layers. Cook on the stovetop for 10 minutes.
Run a spatula around the edges of the gratin and transfer the pan to the oven. Bake for 20 minutes, until the edges are starting to color; the top will seem a bit dry at this point, but don’t let it concern you, it won’t be for long.
Remove the pan from the oven and run your spatula around the edges again. Very carefully, invert the pan onto a large plate (a rimless cookie sheet or pizza peel works really well here, too) so the gratin comes out upside down. If it doesn’t come out all in one piece, don’t worry … it’s forgiving. Gently slide the gratin back into the skillet so that the top is now on the bottom. Use your spatula to tuck in the edges and shape the gratin again, then return the pan to the oven for 15-20 more minutes.
Remove from oven and let sit for 5 minutes before serving. Cut into wedges and serve as a side dish, or as the main attraction with Braised Kale Trio.