Ultimate Onion Tart Recipe

Introduction

This ultimate onion tart is a savory delight that combines sweet, slow-cooked onions with a creamy, cheesy filling nestled in a crisp shortcrust pastry. Perfect for a comforting lunch or a stylish starter, it’s sure to impress with rich flavors and a tender texture.

Ingredients

• 300g shortcrust pastry, thawed if frozen
• 25g butter
• 2 tbsp olive oil
• 900g onions, halved and thinly sliced
• 2 medium eggs
• 300ml double cream
• 40g vegetarian parmesan-style cheese, grated

Instructions

1. Step 1: Heat the oven to 190°C (fan 170°C/gas mark 5). Roll out the pastry on a lightly floured surface and use it to line a deep 23cm fluted flan tin. Line the pastry with baking paper and fill with baking beans. Bake blind for 15 minutes.
2. Step 2: While the pastry bakes, heat the butter and olive oil in a large frying pan. Add the sliced onions, cover, and gently fry for about 30 minutes until completely softened but still pale in color.
3. Step 3: In a bowl, beat together the eggs and double cream. Add the grated cheese and season to taste with salt and pepper. Stir in the softened onions, then spoon the mixture into the pre-baked pastry case.
4. Step 4: Return the tart to the oven and bake for 25–30 minutes until the filling is lightly set and nicely browned on top. Allow to cool slightly before serving.

Tips & Variations

• For extra flavor, sprinkle fresh thyme or rosemary over the onions while cooking.
• Try using caramelized onions instead of gently fried for a sweeter, deeper taste.
• Swap the vegetarian parmesan-style cheese for mature cheddar or Gruyère for a different cheese twist.
• If you prefer a lighter tart, substitute half the double cream with whole milk.

Storage

Store any leftover tart in an airtight container in the refrigerator for up to 2 days. Reheat gently in a low oven or microwave until warmed through. The tart is best enjoyed fresh, as the pastry may become softer after storing.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I prepare the tart in advance?

Yes, you can prepare the filling and blind bake the pastry crust a day ahead. Assemble and bake the tart just before serving for the best texture.

Can I use frozen pastry instead of fresh?

Absolutely. Thaw frozen shortcrust pastry completely before rolling out and follow the recipe steps as usual.

Ultimate Onion Tart Recipe

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★★★★★

4.9 from 102 reviews

• Author: Jake
• Total Time: 1 hour 10 minutes
• Yield: 8 servings 1x
• Diet: Vegetarian

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Description

This Ultimate Onion Tart is a rich and savory dish featuring a buttery shortcrust pastry filled with slowly caramelized onions blended with a creamy egg and vegetarian parmesan-style cheese mixture. It’s perfect as a comforting lunch or a flavorful brunch centerpiece, combining a delicate crisp crust with a luscious, soft filling.

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Ingredients

Scale 1x2x3x

Pastry

• 300g shortcrust pastry, thawed if frozen

Filling

• 25g butter
• 2 tbsp olive oil
• 900g onions, halved and thinly sliced
• 2 medium eggs
• 300ml double cream
• 40g vegetarian parmesan-style cheese, grated
• Salt and freshly ground black pepper, to taste

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Instructions

1. Prepare the pastry case: Heat the oven to 190°C (170°C fan)/gas mark 5. On a lightly floured surface, roll out the shortcrust pastry and use it to line a deep 23cm fluted flan tin. Line the pastry with baking paper and fill with baking beans to prevent the base from rising, then blind bake for 15 minutes.
2. Cook the onions: While the pastry bakes, heat the butter and olive oil in a large frying pan over medium heat. Add the sliced onions, cover the pan, and gently fry for about 30 minutes. Stir occasionally until the onions are completely softened but still pale, avoiding browning to maintain a delicate flavor.
3. Prepare the filling: In a mixing bowl, beat together the eggs and double cream until smooth. Stir in the grated vegetarian parmesan-style cheese and season the mixture with salt and freshly ground black pepper to taste. Then gently fold the cooked onions into this cream mixture.
4. Assemble and bake the tart: Remove the baking beans and parchment paper from the partially baked pastry shell. Spoon the onion and egg-cream filling evenly into the flan case. Return to the oven and bake for 25-30 minutes, until the filling is lightly set and the top is golden brown.
5. Cool and serve: Allow the tart to cool slightly before slicing. This helps the filling set further for neat serving. Enjoy warm or at room temperature.

Notes

• You can substitute vegetarian parmesan-style cheese with regular parmesan if not strictly vegetarian.
• For a deeper caramelized flavor, onions can be cooked for longer but watch to prevent browning.
• If short on time, pre-made shortcrust pastry from the store works perfectly.
• This tart pairs wonderfully with a fresh green salad and a light vinaigrette.
• Leftovers can be refrigerated for up to 2 days and reheated gently in the oven.

• Prep Time: 15 minutes
• Cook Time: 55 minutes
• Category: Savory Tart
• Method: Baking
• Cuisine: European

Keywords: onion tart, savory tart, vegetarian tart, baking, shortcrust pastry, creamy filling