Save to Pinterest My neighbor handed me a bag of onions from her garden one autumn afternoon, far more than I could use before they sprouted. I stood in my kitchen wondering what to do with them all when I remembered a tart I'd seen in a cafe window in Lyon years ago. The onions caramelized slowly on the stove, filling the house with a smell so sweet and savory that my husband wandered in twice asking when dinner would be ready. That tart became our Sunday ritual.
I made this for a baby shower once, cutting it into small squares and watching them disappear faster than anything else on the table. One guest asked if I'd trained in France, which made me laugh because I'd learned it from trial and error in my tiny apartment kitchen. The key was patience with those onions, something I didn't have the first time I tried and ended up with burnt bits instead of silky strands. Now I put on music and let them do their slow magic while I prep everything else.
Ingredients
- Puff pastry: Store bought works beautifully here and saves you an hour of work, just make sure it's fully thawed so it doesn't crack when you unroll it.
- Yellow onions: They have the right sugar content to caramelize properly, don't substitute red onions unless you want a sharper, less sweet result.
- Butter and olive oil together: This combination prevents burning while adding richness, I learned this after scorching a pan using only butter.
- Sugar: Just a teaspoon helps the onions release their natural sweetness faster, though they'll get there eventually without it.
- Fresh thyme: It cuts through the richness with a woodsy note, dried works but use half the amount or it overpowers everything.
- Goat cheese: Look for one that's creamy and tangy, not chalky, the quality makes a real difference in each bite.
- Eggs and cream: They create a custard that holds everything together without feeling heavy, whole milk thins it just enough.
Instructions
- Prepare the crust:
- Press the pastry into your tart pan gently, letting it settle into the corners without stretching or it'll shrink back in the oven. Pricking the base with a fork stops it from puffing up and creating air pockets under your filling.
- Caramelize the onions:
- This step takes patience and a medium flame, not high or they'll brown on the edges before softening in the middle. Stir them every few minutes and when they start sticking to the pan, that's when the magic happens and they turn golden and jammy.
- Make the custard:
- Whisk until the eggs are fully blended with the cream so you don't get streaks of white in the baked tart. Season it well because pastry and onions both need the support of salt and pepper.
- Assemble:
- Spread the cooled onions first so they form an even layer, then scatter the goat cheese so every slice gets some. Pour the custard slowly from the center outward so it distributes evenly without disturbing your carefully arranged filling.
- Bake until set:
- The tart is done when the center barely jiggles and the edges have puffed and turned golden. Let it rest for ten minutes or the custard will run when you slice it, I learned that the messy way.
Save to Pinterest My daughter requested this for her birthday dinner instead of cake one year, which tells you how good it is. We sat outside with it still warm from the oven, the crust shattering under our forks, and she said it tasted like something you'd order somewhere fancy. I didn't tell her how simple it actually was to make.
Make Ahead Tips
You can caramelize the onions up to three days ahead and keep them in the fridge, which cuts your active time in half on the day you want to serve it. The whole tart also reheats well, ten minutes in a moderate oven brings it back to life without drying it out. I've even assembled it completely and frozen it unbaked, then added ten extra minutes to the baking time straight from the freezer.
Flavor Variations
A splash of balsamic vinegar in the last minutes of cooking the onions adds a dark, tangy edge that some people prefer to the pure sweetness. Feta gives you a saltier, crumblier texture than goat cheese, while blue cheese turns it into something bold and punchy for people who like strong flavors. I've also tucked in some sauteed mushrooms or crispy bacon when I'm feeling indulgent, both work beautifully with the onions.
Serving Suggestions
This tart shines with a simple arugula salad dressed in lemon and olive oil, the peppery greens cut through the richness perfectly. A chilled white wine, especially something crisp like Sauvignon Blanc, makes it feel like a special occasion even on a weeknight.
- Slice it into small squares for an elegant appetizer that holds up at room temperature during a party.
- Serve it warm for brunch with a poached egg on top and watch everyone's face light up.
- Pack a slice for lunch with some fruit and cheese, it travels well and tastes even better the next day.
Save to Pinterest This tart has earned a permanent spot in my repertoire, the kind of recipe I turn to when I want to feel like I've made something beautiful without spending all day in the kitchen. I hope it becomes one of those recipes for you too, the kind you make again and again until you don't need to look at the instructions anymore.
Recipe FAQs
- → How do I caramelize onions perfectly?
Cook sliced onions slowly over medium heat with olive oil and butter, stirring often. Add sugar and salt to enhance sweetness, and thyme for aroma. It usually takes 20-25 minutes until they turn deep golden and soft.
- → Can I use different cheese instead of goat cheese?
Yes, alternatives like feta or blue cheese provide unique tangy profiles, which complement the sweetness of the onions and add depth to the tart.
- → What type of pastry works best for this tart?
Ready-rolled puff pastry or a homemade shortcrust pastry both work well, offering a flaky and buttery base that holds the filling perfectly.
- → How should I serve this tart?
It’s excellent warm or at room temperature, garnished with fresh chives or parsley. Pairs nicely with a crisp green salad and a chilled Sauvignon Blanc.
- → Can I add extra flavor to the onions?
Adding a splash of balsamic vinegar during the last minutes of cooking adds a rich, tangy depth that enhances the caramelized sweetness.