This savory onion and mushroom tart is a beautiful blend of earthy mushrooms, sweet caramelized onions, and creamy cheeses all wrapped in a buttery, flaky crust. It’s the kind of dish that feels fancy enough for a dinner party but is easy enough to make on a weeknight. Each bite brings together deep umami flavors and comforting richness, perfect as an appetizer, brunch item, or a light vegetarian main course.

Why You’ll Love This Recipe

• Combines rich, savory flavors with a flaky homemade crust

• A versatile dish that works as a main, starter, or side

• The filling can be made ahead of time

• Simple ingredients, big payoff in flavor

• Can be served warm, room temperature, or cold

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

• 1 ¼ cups all-purpose flour

• ½ teaspoon salt

• 8 tablespoons (1 stick) unsalted butter, cold and cut into small cubes

• 3 to 4 tablespoons ice water

For the filling:

• 1 tablespoon olive oil

• 1 tablespoon unsalted butter

• 2 medium yellow onions, thinly sliced

• 2 tablespoons balsamic vinegar

• 1 teaspoon sugar

• 8 ounces mushrooms (such as cremini or button), cleaned and sliced

• Salt and freshly ground black pepper, to taste

• ¾ cup ricotta cheese

• ¼ cup grated Parmesan cheese

• 1 large egg

• 2 tablespoons heavy cream

• 2 tablespoons chopped chives or green onions (for garnish)

Directions

1. Prepare the tart crust: In a large bowl, whisk together the flour and salt. Add cold butter and cut it in using a pastry cutter or your fingertips until the mixture resembles coarse crumbs. Gradually add the ice water, one tablespoon at a time, mixing until the dough comes together. Form into a disk, wrap in plastic, and refrigerate for at least 30 minutes.

2. Roll and pre-bake the crust: On a floured surface, roll out the dough into a circle about 11 inches in diameter. Fit it into a 9-inch tart pan, trimming any excess. Prick the base with a fork. Line with parchment paper, fill with pie weights or dried beans, and bake in a 375°F (190°C) oven for 15 minutes. Remove weights and bake for 5 more minutes until lightly golden. Let cool.

3. Cook the onions: In a skillet over medium heat, heat the olive oil and butter. Add the sliced onions and cook slowly until soft and golden, about 15 minutes. Stir in the balsamic vinegar and sugar, and continue cooking for another 5 minutes until jammy. Season with salt and pepper. Set aside.

4. Cook the mushrooms: In the same skillet, add a touch more oil if needed and sauté the sliced mushrooms over medium-high heat until browned and their moisture evaporates, about 10 minutes. Season lightly with salt and pepper. Let cool slightly.

5. Make the filling: In a medium bowl, mix together the ricotta, Parmesan, egg, and cream until smooth. Stir in the cooked onions and mushrooms until well combined. Taste and adjust seasoning.

6. Assemble the tart: Pour the filling into the pre-baked tart shell and smooth the top. Sprinkle with chopped chives or green onions.

7. Bake the tart: Return the tart to the oven and bake at 375°F (190°C) for 25–30 minutes, or until the filling is set and the top is lightly golden.

8. Cool and serve: Allow the tart to cool for 10–15 minutes before slicing. Serve warm or at room temperature.

Servings and timing

• Servings: 6–8 slices

• Prep time: 45 minutes

• Cook time: 30–35 minutes

• Total time: Approximately 1 hour 20 minutes

Variations

• Cheese swap: Use goat cheese or feta in place of ricotta for a tangier flavor.

• Add greens: Stir in sautéed spinach or kale for extra nutrition and color.

• Mushroom mix: Use a combination of shiitake, oyster, and cremini for a more complex flavor.

• Add herbs: Add chopped thyme, rosemary, or tarragon to the filling for a herby note.

• Mini tarts: Divide dough and filling among small tart pans for individual portions.

• Crust shortcut: Use store-bought pie dough or puff pastry if you’re short on time.

Storage/Reheating

• Refrigerator: Store leftover tart, tightly covered, in the fridge for up to 4 days.

• Reheat: Warm in a 325°F (160°C) oven for about 10–12 minutes. This helps retain the crust’s crispness.

• Freezing: Freeze fully baked tart slices wrapped tightly for up to 1 month. Thaw overnight in the fridge, then reheat before serving.

FAQs

How thin should the tart crust be?

Roll the dough to about ⅛ inch thickness for an even, crisp crust that isn’t too thick or doughy.

Can I make the crust ahead of time?

Yes, the dough can be made and refrigerated for up to 2 days, or frozen for up to a month. Thaw in the fridge before using.

What’s the best type of mushroom to use?

Cremini mushrooms work well, but a mix of wild mushrooms adds depth and complexity to the flavor.

Can I use store-bought crust?

Yes, a pre-made tart shell, pie crust, or even puff pastry can be used for convenience.

Can I make this tart without eggs?

The egg helps bind the filling, but you could try a flax egg or omit it for a softer texture. The tart may not set as firmly.

Can this tart be served cold?

Yes, it’s delicious served at room temperature or chilled, making it perfect for picnics or lunchboxes.

What’s a good side dish for this tart?

A fresh green salad with a tangy vinaigrette or a bowl of tomato soup pairs beautifully.

Can I make this gluten-free?

Yes, use a gluten-free flour blend in the crust or substitute with a gluten-free tart shell.

How do I keep the bottom crust from getting soggy?

Blind baking and cooling the crust before adding the filling helps. Also, avoid overfilling with overly wet ingredients.

How long can the filling sit before baking?

The filling can be made and refrigerated up to 24 hours ahead. Let it come to room temperature before spreading into the crust.

Conclusion

This onion and mushroom tart delivers bold, satisfying flavors wrapped in a buttery, golden crust. It’s elegant yet uncomplicated, making it perfect for everyday meals or special occasions. With customizable ingredients and the option to make components ahead of time, it’s a go-to dish you’ll reach for again and again.