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Caramelized Onion Tartlets

With caramelized onion, fresh thyme, and Gruyere cheese these Caramelized Onion Tartlets have the same flavor profile as French Onion Soup, but with a buttery extra flaky crust.
Course Appetizer, Snack
Cuisine American
Prep Time 1 hour
Cook Time 1 hour 15 minutes
Servings 12 servings
Calories 329kcal

Ingredients

Crust:

  • 2 1/4 cups all-purpose flour plus more for rolling out the dough
  • 1/4 cup Argo Corn Starch
  • 3/4 teaspoon salt
  • 1 cup unsalted butter chilled and diced
  • 3/4 cup ice-cold water plus more as needed

Filling:

  • 2 tablespoons unsalted butter
  • 3 small-medium yellow onions peeled and thinly sliced
  • 1/2 teaspoon salt
  • 1/2 teaspoon black pepper
  • 1 clove garlic peeled and crushed
  • 1 teaspoon minced fresh thyme leaves
  • 2 large eggs
  • 1/4 cup heavy whipping cream
  • 4 teaspoons Argo Corn Starch dissolved in 1/4 cup cold water to make a slurry
  • 4 ounces Gruyere cheese shredded

Instructions

For the Crust:

  • Whisk together the flour, corn starch, and salt, and then use a fork or pastry cutter to cut in the diced butter.
  • Adding 2 tablespoons of ice-cold water at a time, work in enough water so that it forms a dough and you can squeeze it into a ball.
  • Shape the dough into a disk, wrap it in plastic wrap, and refrigerate to chill, about 30 minutes to 1 hour. Or you can chill the dough for up to 3 days and let it sit at room temperature for about 15 minutes before rolling it out.

For the Filling:

  • Add the butter to a large, heavy-bottomed skillet over medium heat.
  • Once melted, add the onion and cook until the onion is melted down into a rich golden brown color, about 35 to 45 minutes. Stir frequently and turn the heat down or add a splash of water as necessary to prevent the onion from burning.
  • Add the salt, black pepper, garlic, and thyme and cook 1 minute more, stirring constantly. Cool.
  • Whisk together the eggs, cream, and corn starch slurry in a large bowl, and then whisk in the cooled caramelized onion. Whisk in the cheese.

To Assemble and Bake the Tartlets:

  • Preheat the oven to 375F.
  • Roll out the disk of dough on a lightly floured surface to a circle about 14 inches in diameter.
  • Use a 3-inch cookie cutter (or a glass with that diameter) to stamp out circles in the dough. Gather the scraps of dough, re-roll them, and continue stamping out circles until the dough is gone.
  • Press each dough circle into the well of a mini muffin tray. Fill each tart with 1 tablespoon of caramelized onion filling.
  • Bake until the crust is golden and the filling is set, about 25 to 30 minutes.
  • Let the tartlets cool until you can handle them, and then pop each one out of the mini muffin tray.
  • Serve warm or at room temperature.

Notes

  • This recipe makes 48 tartlets for a total of 12 servings. Each serving is 4 tartlets.
  • Store these tartlets wrapped in the fridge for up to 5 days.
  • To reheat these tartlets, place them on a baking tray and heat in a 375F oven until warm, about 8 minutes.

Nutrition

Serving: 4tartlets | Calories: 329kcal | Carbohydrates: 24g | Protein: 7g | Fat: 23g | Saturated Fat: 14g | Cholesterol: 90mg | Sodium: 291mg | Potassium: 91mg | Fiber: 1g | Sugar: 1g | Vitamin A: 741IU | Vitamin C: 2mg | Calcium: 117mg | Iron: 1mg