Save I stumbled into this tart on a rainy Saturday when I had four onions about to turn and a friend coming over who claimed she didn't like eggs. The slow sizzle of those onions transforming into something sweet and jammy filled the whole apartment, and by the time she arrived, she was already asking what smelled so good. We ate the entire tart between us, straight from the pan, standing at the counter. She never mentioned the eggs.
I've brought this tart to potlucks, served it at lazy Sunday brunches, and once even packed it for a picnic where it survived a bumpy bike ride and still impressed. There's something about the contrast between the flaky crust, the soft onions, and that tangy goat cheese that makes people pause mid-conversation. It's become my go-to when I want to feel like I tried without actually spending all day in the kitchen.
Ingredients
- Puff pastry: The buttery, flaky foundation that makes this feel special without any rolling or crimping stress.
- Yellow onions: They need time to caramelize properly, don't rush them or they'll taste sharp instead of sweet.
- Olive oil and butter: The combination gives you flavor and prevents burning while the onions slowly collapse into golden strands.
- Sugar: Just a teaspoon coaxes out the natural sweetness and speeds up the browning.
- Thyme: Fresh is lovely, but dried works just fine and adds that earthy note that makes the whole thing smell like a French kitchen.
- Goat cheese: Crumbly and tangy, it balances the sweetness of the onions and melts into creamy pockets.
- Eggs, cream, and milk: This custard holds everything together and bakes up soft and silky, not rubbery.
- Black pepper and salt: Season each layer as you go, it makes a difference you can taste.
- Chives or parsley: A fresh green finish that cuts through the richness and makes it look like you know what you're doing.
Instructions
- Prep the crust:
- Preheat your oven to 200°C (400°F). Press the pastry into a 23 cm tart pan, trim the edges, and prick the base all over with a fork to keep it from puffing up. Chill it while you work on the onions.
- Caramelize the onions:
- Heat olive oil in a large skillet over medium heat, add the sliced onions, and stir them every few minutes. After about 10 minutes they'll soften, then add butter, sugar, salt, and thyme. Keep cooking and stirring occasionally until they turn deep golden and sweet, around 20 to 25 minutes total. Let them cool slightly before using.
- Make the custard:
- Whisk together eggs, cream, milk, pepper, and salt in a bowl until smooth and well combined.
- Assemble the tart:
- Spread the cooled caramelized onions evenly over the chilled pastry, then scatter the crumbled goat cheese on top. Pour the custard mixture gently over everything, making sure it reaches the edges.
- Bake:
- Slide the tart into the oven and bake for 25 to 30 minutes, until the filling is set and the top is lightly golden. Let it cool for 10 minutes before slicing so the custard firms up and doesn't run everywhere.
- Garnish and serve:
- Sprinkle fresh chives or parsley and a crack of black pepper over the top. Serve it warm or at room temperature, both are delicious.
Save The first time I served this to my mom, she asked for the recipe halfway through her first slice. She doesn't usually ask for recipes. I wrote it down on the back of an envelope and she still has it tucked in her cookbook, smudged with butter and thyme. That's when I knew this one was a keeper.
Flavor Swaps and Variations
If goat cheese isn't your thing, crumbled feta adds a salty bite, or try blue cheese for something bold and funky. A splash of balsamic vinegar stirred into the onions during the last few minutes of cooking adds a sweet-tart edge that's hard to resist. I've also thrown in a handful of wilted spinach or sun-dried tomatoes when I had them around, and it worked beautifully.
Serving Suggestions
This tart pairs perfectly with a simple green salad dressed in lemon and olive oil, something crisp to cut through the richness. I like it with a chilled Sauvignon Blanc or a light rosé, but honestly it's just as good with sparkling water and good company. It works as a main dish, a fancy brunch centerpiece, or sliced into small wedges for an elegant appetizer.
Make Ahead and Storage
You can caramelize the onions a day or two ahead and keep them covered in the fridge, which saves you the longest step when you're ready to bake. The baked tart keeps well in the fridge for up to three days, and I've reheated slices gently in a low oven or eaten them cold straight from the container. It doesn't freeze beautifully because of the custard, but it rarely lasts long enough for that to matter.
- Caramelize onions in advance and store them covered in the fridge.
- Reheat leftovers gently in a low oven to keep the crust crisp.
- Serve leftovers cold for breakfast, it's surprisingly perfect that way.
Save This tart has gotten me out of more last-minute hosting jams than I can count, and it never fails to make people feel special. I hope it does the same for you.
Recipe FAQs
- → How do I caramelize onions properly?
Cook thinly sliced onions over medium heat with olive oil, butter, sugar, salt, and thyme, stirring often for 25 minutes until deep golden and sweet.
- → Can I substitute goat cheese with another cheese?
Yes, alternatives like feta or blue cheese work well to maintain the tart’s tangy flavor profile.
- → What pastry works best for this tart?
Ready-rolled puff pastry or homemade shortcrust both provide a flaky and sturdy base suitable for the filling.
- → Is this tart suitable for vegetarians?
Yes, it uses no meat or gelatin, making it vegetarian-friendly.
- → How should I serve this tart?
Serve warm or room temperature, garnished with fresh chives or parsley, alongside a crisp green salad or a chilled white wine.
- → Can I add extra flavor to the onions?
Adding a splash of balsamic vinegar in the last minutes of cooking enhances the sweetness and depth.