- 1 teaspoon unsalted butter
- 2 tablespoons olive oil
- 6 ounces pancetta or bacon, cut into 3/4 inch pieces
- 2 large yellow onions, peeled and thinly sliced
- Freshly ground black pepper
- 1 tablespoon minced garlic
- 1 tablespoon fresh thyme
- 6 ounces kale, Swiss chard, or spinach (tough stems removed and well rinsed)
- 2 pounds all purpose potatoes, like white rose or long whites, peeled and cut into 1/4-inch thick slices
- 1 cup grated Gruyere, or Swiss cheese
- 1 1/2 cups heavy cream
Preheat the oven to 375 degrees F. Butter a 2-quart baking dish and set aside on a rimmed baking sheet.
In a large skillet, heat the olive oil over medium-high heat. Add the pancetta and cook, stirring, until golden brown, about 4 minutes. Add the onions and season with salt and pepper and cook, stirring, until the onions begin to caramelize, about 20 minutes. Add the thyme and garlic and cook 1 minute.
Bring a large pot of water to a boil. Add the kale and blanch until tender, about 3 minutes. Drain and squeeze on towels to remove excess liquid.
Spread a layer of potatoes in the bottom of the prepared dish, slightly overlapping the slices. Season with Essence, and top with a layer of the onions. Place a layer of Swiss chard on top, followed by more potatoes and onions. Repeat with remaining ingredients. Add the cream, top with cheese and cover with foil. Roast until nearly all the liquid has been absorbed, about 1 hour and 15 minutes.
Remove the foil and continue baking until golden brown and bubbly, an additional 15 to 20 minutes. Remove from the oven and let sit for 10 minutes before serving.