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Easy Onion Tart

This onion tart is all about comfort and flavor. Sweet golden onions melt into a creamy custard, while the buttery crust bakes up perfectly crisp. It’s the kind of recipe that feels special but is simple enough to make anytime.
Print Recipe
Prep Time:30 minutes
Cook Time:50 minutes
Total Time:1 hour 20 minutes

Ingredients

For the crust:

  • 1 2/3 cups all-purpose flour
  • 7 tbsp butter cold and cubed
  • 1 egg
  • Pinch of salt
  • 1-2 tbsp cold water

For the filling:

  • 3-4 yellow onions thinly sliced
  • 2 tbsp butter
  • 1/2 cup heavy cream
  • 2 large eggs
  • 1 cup grated hard cheese such as Gruyère, Parmesan, or Cheddar
  • Salt and black pepper to taste
  • Pinch of nutmeg optional

Instructions

  • n a large bowl, mix the flour and salt. Cut in the butter until the mixture resembles coarse crumbs.
  • Add the egg and just enough cold water to form a smooth dough. Shape into a ball, wrap, and chill for 30 minutes.
  • While the dough chills, melt the butter in a skillet over medium heat. Add onions and cook, stirring often, until golden and caramelized, about 20 minutes.
  • In a separate bowl, whisk together cream and eggs. Stir in grated cheese, salt, pepper, and nutmeg.
  • Roll out the dough on a floured surface and fit into a 9-inch tart pan. Trim edges. Prick the bottom with a fork. Line with parchment and fill with pie weights. Bake at 350°F for 10 minutes.
  • Remove parchment and weights. Spread caramelized onions over the crust, then pour the cream mixture on top.
  • Return to the oven and bake 25–30 minutes, until the filling is golden and set.
  • Let cool slightly before slicing. Serve warm or at room temperature.

Notes

  • Caramelize onions slowly over medium heat for the best flavor.
  • Blind baking is essential to prevent a soggy crust.
  • This tart is delicious warm or chilled, making it great for leftovers.
Servings: 8