Save to Pinterest There was this afternoon last spring when I opened the fridge and found nothing but onions, a log of goat cheese, and some leftover puff pastry. Instead of ordering takeout, I sliced those onions paper-thin and let them cook low and slow until my kitchen smelled like a French bistro. What started as improvisation turned into one of my most requested dishes. Now I make this tart whenever I want to feel like I'm treating myself to something special, even on an ordinary Tuesday.
I brought this tart to a potluck once, still warm in the pan, wrapped in a kitchen towel. A friend took one bite and asked if I'd secretly trained at culinary school. I laughed and told her the truth: patience with the onions is the only skill required. By the end of the night, three people had taken photos of the recipe scribbled on the back of a napkin. That's when I realized this wasn't just a tart—it was a little piece of kitchen magic I could share.
Ingredients
- Ready-rolled puff pastry: Using store-bought pastry isn't cheating, it's smart, and it gives you a buttery, flaky base without the fuss of making dough from scratch.
- Yellow onions: They have the perfect balance of sweetness and sharpness, and they caramelize beautifully when cooked low and slow with a little fat and patience.
- Olive oil and butter: The olive oil keeps the onions from sticking, while the butter adds a rich, nutty depth that makes all the difference.
- Sugar: Just a teaspoon helps the onions release their natural sugars and turn that gorgeous golden-brown color faster.
- Fresh thyme: This herb has an earthy, slightly floral note that feels like it was made to live alongside caramelized onions.
- Goat cheese: Creamy, tangy, and a little funky in the best way, it cuts through the sweetness and adds a luxurious texture.
- Eggs, cream, and milk: These create a silky custard that binds everything together and bakes into a tender, custardy filling.
- Black pepper and salt: Simple seasonings that let the other flavors shine without getting in the way.
- Fresh chives or parsley: A handful of green herbs at the end adds a pop of color and a fresh, bright finish.
Instructions
- Prep the Pastry:
- Preheat your oven to 200 degrees Celsius and press the puff pastry gently into a 23 cm tart pan, letting any excess drape over the edges before trimming it away with a knife. Prick the base all over with a fork to prevent puffing, then slide it into the fridge for 10 minutes so it holds its shape beautifully in the oven.
- Caramelize the Onions:
- Heat olive oil in a large skillet over medium heat, add the sliced onions, and stir them every few minutes as they soften and start to turn translucent, which takes about 10 minutes. Toss in the butter, sugar, salt, and thyme, then lower the heat slightly and keep stirring occasionally until the onions are deeply golden, sweet, and almost melting, which can take another 20 to 25 minutes—this is where the magic happens, so don't rush it.
- Make the Custard:
- In a mixing bowl, whisk together the eggs, cream, milk, pepper, and salt until everything is smooth and well combined. The mixture should look silky and pale yellow, ready to cradle all those caramelized onions.
- Assemble the Tart:
- Spread the cooled caramelized onions evenly across the chilled pastry base, then scatter the crumbled goat cheese over the top so every bite gets a little tangy creaminess. Pour the custard gently over the filling, letting it settle into all the nooks and crannies without overflowing.
- Bake Until Golden:
- Slide the tart into the preheated oven and bake for 25 to 30 minutes, until the custard is just set with a slight jiggle in the center and the edges are lightly golden. Let it cool in the pan for 10 minutes before slicing so the filling firms up and doesn't spill everywhere.
- Garnish and Serve:
- Sprinkle fresh chives or parsley over the top and add a few cracks of black pepper for a little extra bite. Serve it warm, at room temperature, or even cold the next day—it's delicious every way.
Save to Pinterest One quiet Sunday morning, I made this tart and ate a slice with my coffee while the house was still calm and the light was soft through the kitchen window. It wasn't for anyone else, just me, and that felt like the ultimate luxury. Sometimes the best meals are the ones you make just because you deserve something beautiful and delicious, no occasion required.
How to Get Perfectly Caramelized Onions
The secret is time and temperature—medium to medium-low heat, plenty of stirring, and at least 20 minutes on the stove. If the pan gets too dry, add a splash of water or white wine to deglaze and keep things moving. You'll know they're ready when they're soft, sticky, and the color of dark honey.
Make-Ahead and Storage Tips
You can caramelize the onions up to two days ahead and keep them in the fridge, which makes assembly a breeze when you're short on time. The baked tart stores well in the fridge for up to three days and reheats beautifully in a low oven. I've even frozen slices wrapped tightly in foil, then thawed and warmed them for a quick lunch that tastes homemade.
Serving Suggestions and Pairings
This tart shines alongside a crisp green salad with a lemony vinaigrette, or you can serve it with roasted vegetables for a more substantial meal. A chilled glass of Sauvignon Blanc or a light Pinot Noir complements the tangy goat cheese and sweet onions perfectly. It also makes a stunning brunch centerpiece when cut into small squares and served on a platter with fresh fruit.
- Add a drizzle of balsamic reduction over each slice for a glossy, slightly sweet finish.
- Swap the goat cheese for crumbled feta or a sharp blue cheese if you want a bolder, saltier flavor.
- Toss in a handful of toasted walnuts or pine nuts for a little crunch and extra richness.
Save to Pinterest This tart has become my go-to whenever I want to remind myself that cooking doesn't have to be complicated to feel special. It's proof that a few simple ingredients, treated with care and patience, can turn into something truly memorable.
Recipe FAQs
- → How do you caramelize onions properly?
Sauté sliced onions in olive oil over medium heat, stirring often. Add butter, sugar, salt, and thyme, then cook slowly until onions turn deep golden and soft, about 20–25 minutes.
- → Can I use another type of cheese?
Yes, feta or blue cheese can be used instead of goat cheese for different flavor profiles, adding tang or sharpness to the tart.
- → What is the best pastry for this tart?
A ready-rolled puff pastry works well for a flaky crust, but homemade shortcrust pastry offers a sturdier, buttery base depending on preference.
- → How should this tart be served?
Serve warm or at room temperature, optionally garnished with chopped fresh chives or parsley, accompanied by a crisp salad and white wine.
- → Can I prepare the onions in advance?
Yes, caramelized onions can be made ahead and refrigerated for up to 2 days, saving time on the day of assembly.