Kale and Caramelized Onion Gratin

Kale and Caramelized Onion Gratin

By: Marge Perry & David Bonom

Caramelized onions may be the key to all culinary success—they make everything taste better!

Serves 6


  • 3 tablespoons unsalted butter
  • 4 cups red onion
  • 2 tablespoons sugar
  • 1 teaspoon fresh thyme leaves
  • 3/4 teaspoon salt
  • 1/2 teaspoon ground black pepper
  • 2 bunches kale, ribs removed, torn into 1 1/2-inch pieces
  • 225g Gruyere cheese, shredded
  • 1/2 cup Parmesan cheese, grated
  • 2 1/2 cups heavy cream


  1. Melt 1 tablespoon of the butter in a large Anolon skillet over medium heat. Add the onion, sugar, thyme, 1/4 teaspoon of the salt and 1/4 teaspoon of the pepper; cook, stirring occasionally, until golden, about 18-20 minutes. Transfer to a bowl.
  2. Preheat the oven to 215°C/425°F.
  3. Wipe out the skillet and melt 1 tablespoon of the remaining butter over medium heat. Add half of the kale and cook, tossing, until slightly wilted, about 1 1/2 minutes. Transfer kale to the bowl with the onions; repeat with the remaining butter and kale.
  4. Add half of the Gruyere cheese, 1/4 cup of the Parmesan cheese, remaining 1/2 teaspoon salt and 1/4 teaspoon pepper to the kale mixture and toss well. Transfer to a baking tray. Pour the cream over the kale then sprinkle with the remaining Gruyere and Parmesan cheeses.
  5. Bake in the centre of the oven until the cream has thickened and the cheese is golden brown, about 53-55 minutes. Let stand 10 minutes before serving.
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