Save I used to think caramelizing onions was a waste of time until I smelled them turning golden in my pan one Sunday morning. The kitchen filled with this sweet, almost jammy scent, and I realized I'd been missing the whole point of patience. When I pulled that first tart from the oven, the goat cheese had melted into soft pockets against the onions, and the pastry shattered under my fork. I've been making this ever since, usually when I want something that feels fancy but doesn't require me to panic.
I made this for a friend's birthday lunch once, and she kept asking what the secret ingredient was. There wasn't one, just onions that had been given enough time to collapse into themselves. We ate it outside with cold white wine, and I remember thinking how strange it was that something so simple could make a afternoon feel like an occasion. She still asks me to bring it when we get together.
Ingredients
- Puff pastry: Store-bought saves you an hour of work, and honestly, unless you're trying to prove something, it's perfectly flaky and buttery on its own.
- Yellow onions: They have the right balance of sweetness and sharpness, and they break down beautifully when you give them time and a little butter.
- Goat cheese: Tangy and creamy, it cuts through the sweetness of the onions without overpowering them, crumble it unevenly for little pockets of flavor.
- Heavy cream and whole milk: This mixture makes the custard rich but not heavy, you need both for the right texture.
- Fresh thyme: A few leaves add a quiet herbal note that makes the whole tart smell like a French countryside kitchen.
Instructions
- Prepare the crust:
- Roll out your pastry into the tart pan, pressing it gently into the corners, then prick the bottom all over with a fork to keep it from puffing up. Chill it while you work on the onions so it holds its shape in the oven.
- Caramelize the onions:
- Heat the oil in a wide skillet and add the sliced onions, stirring them every few minutes until they soften and start to turn golden. Add the butter, sugar, salt, and thyme, then lower the heat and let them cook slowly until they're deeply caramelized and sweet, this is where the magic happens, so don't rush it.
- Make the custard:
- Whisk together the eggs, cream, milk, pepper, and salt until smooth and pale. It should look silky and just thick enough to coat the back of a spoon.
- Assemble the tart:
- Spread the cooled onions evenly over the chilled crust, then scatter the goat cheese on top in uneven crumbles. Pour the custard gently over everything, letting it settle into the gaps.
- Bake until golden:
- Slide the tart into the hot oven and bake until the custard is set and the top is lightly browned. Let it cool for a few minutes before slicing so the filling doesn't spill out.
Save 
Save There's something about slicing into this tart that makes me slow down. The layers reveal themselves, golden pastry, sweet onions, soft cheese, and I'm reminded that good food doesn't have to be complicated. It just has to be made with a little attention and a lot of butter.
Serving Suggestions
I like to serve this with a simple arugula salad dressed in lemon and olive oil, the peppery greens balance the richness perfectly. A chilled Sauvignon Blanc or a light rosé makes it feel like a proper meal, even if you're just eating it on a weeknight in your pajamas.
Flavor Variations
If you're not a goat cheese person, try crumbled feta or even a sharp blue cheese for something bolder. A splash of balsamic vinegar in the onions during the last few minutes of cooking adds a sweet-tart depth that makes people ask questions. I've also added sautéed mushrooms or roasted red peppers when I had them sitting around, and it worked beautifully.
Storage and Make-Ahead Tips
This tart keeps in the fridge for up to three days, and I've eaten it cold straight from the container more times than I'd like to admit. You can caramelize the onions a day ahead and store them covered, which makes assembly much faster when you're ready to bake.
- Reheat slices in a low oven to bring back the pastry's crispness.
- Freeze the baked tart wrapped tightly for up to a month, thaw and warm before serving.
- If making ahead, assemble everything but wait to pour the custard until just before baking.
Save 
Save This tart has become one of those recipes I turn to when I want to feel like I've made something special without spending all day in the kitchen. It's proof that a few good ingredients and a little patience can turn into something worth sharing.
Recipe Questions & Answers
- → How do I achieve perfectly caramelized onions?
Cook onions slowly over medium heat with olive oil and butter, adding a pinch of sugar and salt to enhance sweetness, stirring frequently until deep golden brown.
- → Can I use a different cheese instead of goat cheese?
Yes, feta or blue cheese offers a distinct flavor twist while maintaining the creamy texture in the tart.
- → What type of pastry is best for this tart?
A ready-rolled puff pastry or homemade shortcrust pastry works well, providing a flaky base that complements the filling.
- → How can I add more depth to the onion flavor?
Add a splash of balsamic vinegar during the last few minutes of cooking the onions to boost their richness.
- → Is this dish suitable for vegetarians?
Yes, the tart is vegetarian-friendly, featuring eggs, dairy, and no meat products.
- → What is the best way to serve this tart?
Serve warm or at room temperature, garnished with fresh chives or parsley, alongside a crisp green salad for balance.