Caramelized Onion & Goat Cheese Tart

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Published July 17, 2026  ·  ⭐ 4.0 (10 reviews)

Prep	Cook	Total	Yield
20 min	1 hr 10 min	1 hr 30 min	6 servings

Difficulty: Medium

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Ingredients

Caramelized onions

• 4 large onions (about 800 g), thinly sliced
• 2 tbsp unsalted butter
• 1 tbsp olive oil
• 1 tsp caster sugar
• 2 tsp fresh thyme leaves
• 1 tbsp balsamic vinegar
• Fine sea salt and black pepper to taste

Assembly

• 1 sheet all-butter puff pastry (about 320 g), thawed
• 150 g soft goat cheese (chevre), crumbled
• 1 egg yolk, beaten with 1 tbsp water
• Fresh thyme leaves for topping
• Flaky sea salt for finishing

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Steps Overview

1. Slowly caramelize the onions until jammy and golden
2. Roll out puff pastry and score a border
3. Top with onions and goat cheese
4. Bake until puffed and golden
5. Finish with thyme and flaky salt

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Step-by-Step

1. Caramelize the onions

Heat the butter and olive oil in a large heavy-based pan over medium heat. Add the sliced onions and a pinch of salt. Cook, stirring occasionally, for 10 minutes until softened. Reduce heat to medium-low, add the sugar, and continue cooking for 30-40 minutes, stirring every few minutes, until the onions are deeply golden and jammy. Stir in the balsamic vinegar and thyme. Season with salt and pepper. Set aside to cool slightly.

2. Prepare the pastry

Preheat the oven to 200 C (fan 180 C). Roll the puff pastry out on a lightly floured surface to about 30 x 25 cm. Transfer to a lined baking sheet. Score a 2 cm border around the edge with a sharp knife, being careful not to cut all the way through. Prick the inner rectangle all over with a fork.

3. Assemble the tart

Spread the caramelized onions evenly over the inner rectangle of pastry. Dot with crumbled goat cheese, pressing the pieces gently into the onions. Brush the pastry border with the egg wash.

4. Bake

Bake for 25-30 minutes until the pastry is puffed and deeply golden and the goat cheese is soft and lightly browned in spots. The border should be tall, flaky, and crisp.

5. Finish and serve

Scatter with fresh thyme leaves and a pinch of flaky sea salt. Serve warm or at room temperature, cut into generous slices. A simple green salad with a mustardy vinaigrette on the side is all you need.

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Notes

• Do not rush the onions. Low and slow is the whole point. If they start catching, add a splash of water and keep going.
• All-butter puff pastry makes a real difference here. Shop-bought is totally fine, just make sure it says "butter" on the box.
• Swap goat cheese for blue cheese (Roquefort or Gorgonzola) if you want something more assertive.
• This tart is great at room temperature, which makes it perfect for picnics and packed lunches.