Belgian Leek Tart with Aged Goat Cheese (Flamiche Aux Poireaux)

From the kitchen of Carly

Buttery pastry cradles creamy leeks and tangy aged goat cheese in this Belgian classic. Caramelized onions mellow into the custard filling, while a tender, flaky crust provides the perfect contrast. Elegant enough for dinner guests, simple enough for weeknight cooking.

Belgian Leek Tart with Aged Goat Cheese (Flamiche Aux Poireaux)

A Belgian classic that sells itself on contrast: a crispy, buttery tart shell holding a creamy custard studded with sweet caramelized leeks and sharp, crumbly goat cheese. The leek confit does the heavy lifting here, so make it ahead and let this elegant tart come together fast. Flamiche asks for nothing fussy, just good ingredients and a hot oven.

Prep
n/a
Cook
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Total
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Servings
4
Difficulty
medium

Ingredients

4 servings

  • 4 tbspice water
  • 3/4 tspapple cider vinegar
  • 1 1/2 cupunbleached all purpose flour
  • 3/4 tspsalt
  • 1/2 cupplus 1 tablespoon chilled unsalted butter
  • 1/2 cupwhole milk
  • 1/2 cupheavy whipping cream
  • 1 largeegg
  • 1 largeegg yolk
  • 1/4 tspsalt
  • 1/2 cupcrumbled aged goat cheese , rind trimmed
  • 1 1/2 cupLeek Confit

Instructions

  1. Stir together 4 tablespoons of ice water and the cider vinegar in a small bowl. Pulse the flour and salt in a food processor to combine, then add the butter and cut it in with short on/off pulses until the mixture looks like coarse meal. With the machine running, pour the water-vinegar mixture in slowly and process until moist clumps form. If the dough looks dry, add more ice water a teaspoon at a time.

  2. Shape the dough into a ball and flatten it into a disk. Wrap it tightly in plastic and refrigerate for at least 2 hours. The dough can be made up to 3 days ahead; just let it soften slightly at room temperature before rolling.

  3. Set a rack in the center of the oven and heat it to 375°F. On a lightly floured surface, roll the dough into a 12-inch round, then lay it into a 9-inch tart pan with a removable bottom. Press the dough against the bottom and up the sides, fold the overhang inward, and press it so the edge sits about 1/2 inch above the rim of the pan. Line the shell with foil, fill it with dried beans or pie weights, and bake until the dough looks dry and set, about 30 minutes. Lift out the foil and beans, then continue baking until the crust turns pale golden, 20 to 25 minutes more. Pull it from the oven and let it cool while you prepare the filling.

  4. In a medium bowl, whisk together the milk, cream, egg, egg yolk, and salt until smooth. Scatter 1/4 cup of the cheese across the bottom of the warm crust, spread the leek confit evenly over it, then top with the remaining cheese. Pour the milk mixture over everything. Bake until the filling has puffed, turned golden in spots, and the center looks set, 35 to 40 minutes. Transfer to a rack to cool slightly, then remove the pan sides and serve warm or at room temperature.

Tips from the kitchen

  • Make the dough 3 days ahead if you can. The cold rest and overnight chill give you more relaxed, flakier results. Pre-bake the crust blind to avoid a soggy bottom, and don't skip the 20-minute final bake once you've removed the weights, it firms the shell and keeps it from sogging under the custard.
  • Leek confit is the star. If you don't have it ready, this tart stalls. Make it a day or two before, then you can assemble and bake this in about an hour.
  • Use aged goat cheese with real tang and crumble, not fresh chevre. Bûcheron or a similar drum works best. The rind is bitter, so trim it as the recipe says.
  • The filling should look barely set in the center when you pull it from the oven. It will continue to firm as it cools. Overbaking dries it out.

Variations

  • Skip the goat cheese and use grated Gruyère or Emmental for a milder, more savory take. The tart becomes more Alsatian and less funky.
  • Add 3 to 4 ounces of smoked ham, diced small, scattered over the leeks before pouring the custard. Flamiche au jambon is traditional in some regions.
  • Use crème fraîche in place of half the heavy cream for a tangier custard that plays well against the sweetness of the leeks.
  • Brush the hot baked crust lightly with Dijon mustard before layering the filling. It adds a whisper of sharpness that cuts through the richness.

Make ahead and storage

Refrigerate leftovers in an airtight container for up to 3 days. Serve cold or at room temperature, or warm gently in a low oven. Do not freeze the assembled tart after baking, but the baked crust and cooked filling can be frozen separately for up to 1 month.