Caramelized Onion Tart

In this Onion Tart the caramelized onions are the star of this show. Though caramelizing onions takes time and patience, the result is well worth the wait. These sweet and smoky onions are added to a custard base, placed in a buttery tart shell, and baked in the EGG until golden brown.


  • ¼ cup extra-virgin olive oil
  • 3 large sweet onions, thinly sliced (about 2 pounds)
  • 1 Tbsp granulated sugar
  • 3 cloves garlic, minced
  • 1 (11-inch) tart shell
  • 1 cup shredded Gruyère cheese
  • 1 cup ricotta cheese
  • 1 cup heavy cream
  • 6 large egg yolks
  • ¼ cup minced fresh chives
  • ¼ tsp ground nutmeg
  • ½ tsp kosher salt
  • ¼ teaspoon freshly ground black pepper
  • ¼ cup grated Parmigiano-Reggiano cheese


Set the EGG for indirect cooking with the convEGGtor at 300°F/149°C.

Heat the olive oil in a Stir-Fry & Paella Pan. Add the onions, sugar and garlic and mix well. Cook for 2 hours, or until the onions are soft and caramel in color. Remove the pan from the EGG and add a Baking Stone to preheat.

Strain the onions, discarding any liquid. Transfer the caramelized onions to the tart shell and spread evenly. Sprinkle the Gruyère cheese over the onions, and distribute the ricotta cheese over the onion mixture by teaspoonfuls. In a small bowl, mix the cream, egg yolks, chives, nutmeg, salt, and pepper. Pour the cream mixture over the tart.

Place the tart on the Baking Stone and close the lid of the EGG. Bake for 15 minutes. Sprinkle the Parmigiano-Reggiano cheese over the tart and bake for an additional 15 minutes, or until the tart is set.

Remove the tart and place on a cooling rack. Let rest for about 45 minutes to an hour, or until firm, before slicing. Serves 8

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