Caramelized Onion Tart is a dish that rewards patience. At first glance, it appears simple — pastry and onions — but its depth comes from time. Properly caramelized onions develop natural sweetness, complexity, and a rich golden color that cannot be rushed.

Unlike heavily topped tarts, this version focuses on balance. The pastry must stay crisp, the onions soft but not mushy, and seasoning controlled. When done well, the flavor feels layered and quietly luxurious.

This tart works beautifully as a light main, appetizer, or part of a seasonal table.

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Ingredients (Serves 4–6)

• 1 sheet shortcrust pastry

• 4 large onions, thinly sliced

• 3 tablespoons olive oil

• 1 tablespoon butter

• 1 teaspoon fresh thyme (optional)

• Salt, to taste

• Freshly ground black pepper

• 1 egg (optional, for egg wash)

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Step-by-Step Instructions (Detailed & Refined)

1. Caramelize the Onions

Heat olive oil and butter in a wide pan over medium-low heat.

Add the sliced onions and a pinch of salt.
Cook slowly for 30–40 minutes, stirring occasionally.

The onions should become soft, golden brown, and sweet — not dark or burnt.

Critical:
Low heat is essential. High heat burns before sweetness develops.

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2. Prepare the Pastry

Preheat oven to 190°C (375°F).

Roll out the pastry onto a lined baking tray.
Lightly score a border around the edges (without cutting through).

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3. Assemble the Tart

Spread the cooled caramelized onions evenly over the pastry, staying inside the border.

Sprinkle thyme and black pepper lightly.

Optional: Brush the border with beaten egg for a golden finish.

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4. Bake

Bake for 20–25 minutes, until the pastry is crisp and golden.

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5. Rest Before Serving

Allow the tart to rest for 5–10 minutes before slicing.

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Professional Tips for Best Results

• Stir occasionally, not constantly, while caramelizing

• Let onions cool slightly before assembling

• Use a wide pan to prevent steaming

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Common Mistakes to Avoid

• Cooking onions on high heat

• Using too much salt early

• Overloading the pastry

• Cutting immediately after baking

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Serving Suggestions

Serve warm or at room temperature with a simple green salad.
Pairs beautifully with light red wine or sparkling water.