Moist Leek Tart with Gruyère and Onions

Why You’ll Love This Recipe

This tart balances creamy richness with subtle sweetness from leeks and onions. The buttery crust gives way to a velvety custard infused with aromatic cumin (if using) and topped with melted Gruyère so good you’ll feel indulgent without the effort.

Ingredients

• 180 g all-purpose flour
• A pinch of salt
• 90 g very cold unsalted butter
• 60 ml chilled water
• 2 leeks, trimmed and thinly sliced (white and light green parts)
• 1 small yellow onion, thinly sliced
• 30 g unsalted butter (or olive oil)
• ½ teaspoon garlic, minced
• 2 large eggs
• 120 ml thick cream
• 1 teaspoon regular salt
• ½ teaspoon black pepper
• 1 teaspoon ground cumin (optional)
• 35 g Gruyère cheese, shredded
  (Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

Directions

1. Make the dough: In a bowl, combine flour and a pinch of salt. Cut the 90 g chilled butter into small cubes and work it into the flour (using fingers or a pastry blender) until the mixture resembles coarse crumbs. Add chilled water gradually until the dough comes together. Form into a disk, wrap, and chill in the fridge for 30 minutes.
2. Preheat oven: Preheat to 375 °F (190 °C).
3. Cook the filling: In a skillet over medium heat, melt the 30 g butter (or heat oil). Add the sliced leeks and onion; sauté until soft and lightly golden, about 8–10 minutes. Stir in the minced garlic and cook 1 minute more. Remove from heat and let cool slightly.
4. Blind bake the crust: Roll out the chilled dough on a lightly floured surface to fit a tart pan (9-inch or similar). Line the pan with the dough, trim edges, and prick the base with a fork. Optionally, line with parchment and weight with baking beans or rice. Bake for 10 minutes, remove weights, and bake another 5 minutes until just set.
5. Prepare custard: In a bowl, whisk together eggs, cream, salt, pepper, and cumin (if using).
6. Assemble: Spread the leek–onion mixture over the pre-baked crust. Pour the custard mixture over evenly. Sprinkle shredded Gruyère on top.
7. Bake: Return to the oven and bake 20–25 minutes, or until the custard is set but still slightly wobbly in the center and the cheese is golden.
8. Cool: Let tart rest for 10 minutes before slicing.

Servings and timing

• Serves: 6 people, depending on serving size.
• Preparation time: ~15 minutes (making dough + sautéing leeks and onions).
• Chill time (dough): ~30 minutes.
• Bake time:
  • Blind baking: ~15 minutes total
  • Final bake: ~20–25 minutes
• Total time: Approximately 1 hour 15 minutes (including chilling).

Variations

• Cheese swap: Try Comté, Fontina, or sharp cheddar in place of Gruyère.
• Herbal note: Add fresh thyme, chives, or tarragon to the custard for brightness.
• Spice adjust: Omit cumin for a classic flavor, or substitute with nutmeg for warmth.
• Vegetable mix-ins: Stir in sautéed mushrooms or wilted spinach for extra earthiness.
• Gluten-free crust: Use a 1:1 gluten-free flour blend for a GF version.

Storage/Reheating

• Refrigerator: Store tart in an airtight container or cover with foil for up to 2–3 days.
• Reheat: Gently warm slices in a 325 °F (165 °C) oven for 8–10 minutes for best texture. Avoid microwaving to preserve the crisp crust.

FAQs

Can I skip chilling the dough?

Chilling helps relax the gluten and keeps the butter cold, which yields a flakier crust. You can proceed without chilling, but expect a denser texture.

Do I have to blind bake the crust?

Yes It prevents the crust from becoming soggy once the wet filling is added and ensures a crisp base.

Can I use half-and-half instead of cream?

Yes. Half-and-half works fine, though the filling will be slightly lighter and less rich.

Can I make this tart ahead of time?

Absolutely. Bake and refrigerate, then reheat before serving for a convenient and elegant dish.

Can I freeze slices?

You can freeze individual slices (wrapped tightly). Thaw overnight in the fridge and reheat in the oven.

How do I know when the custard is set?

The center should be firm but still wobbly carryover heat will finish setting as it cools.

Can I bake it in a different pan?

Yes. A 9-inch pie dish or quiche pan works if you don’t have a tart pan, though flaky edges may vary slightly.

Is it safe to use olive oil instead of butter?

Yes. Olive oil works for sautéing, though the buttery flavor in the crust may be reduced.

Can I halve the recipe?

Certainly. Use a smaller tart or pie dish and adjust baking time as needed start checking around 18 minutes for final bake.

Conclusion

This Moist Leek Tart with Gruyère and Onions is a savory crowd-pleaser with a golden crust, creamy filling, and rich, savory bite. The comforting flavors shine through simply yet elegantly. Perfect for brunch, lunch, or when you want something sophisticated and it’s easier to make than it looks. Enjoy every bite!

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