Classic French Onion Tart
This is the onion tart I think of as French home cooking, not the fancy bakery kind. Puff pastry, a big pile of soft onions, a little custard poured over the top, and the edges of the pastry folded in so it looks rustic on purpose. Six onions sounds like far too many when you’re slicing them. They cook way down.
Take your time with them. I keep the heat at medium-low and let them go soft and sweet without browning, stirring every couple of minutes, about 12 minutes in all. Rushed onions stay sharp and a bit crunchy, and you can taste it. Crème fraîche makes the custard richer than plain milk would, and a pinch of nutmeg is the old-school touch. It’s just as good cold the next day with a green salad.
A classic French onion tart made with puff pastry, slow-cooked onions and a light egg and crème fraîche custard. The pastry edges are folded over the filling, galette-style, so there's no fussy crimping. It bakes in about 40 minutes and slices neatly once it has cooled a little.
Ingredients
Equipment
Method
- Heat the oven to 350°F and line a baking sheet with parchment paper.
- Peel the onions, halve them from root to tip and slice them thinly.6 large yellow onions
- Melt the butter in a large skillet over medium-low heat. Add the onions and cook for 12 to 15 minutes, stirring often, until soft and translucent but not browned. Stir in the thyme, nutmeg, salt and pepper, then take the pan off the heat and let the onions cool slightly.2 tablespoons unsalted butter, 1/2 teaspoon dried thyme, 1 pinch ground nutmeg, 1/2 teaspoon salt, 1/4 teaspoon black pepper
- Whisk the eggs, crème fraîche and milk together in a bowl until smooth.2 large eggs, 3 tablespoons crème fraîche, 2/3 cup whole milk
- Roll the puff pastry into a rough 12-inch round and move it to the lined baking sheet. Spread the onions in the center, leaving a 2-inch border, and pour the custard over them. Fold the border up over the filling, pleating it as you go, and sprinkle the seeds over the pastry.1 sheet frozen puff pastry, 1/2 teaspoon chia or poppy seeds
- Bake for about 40 minutes, until the pastry is puffed and deep golden and the custard is set in the center. Let it cool for 10 minutes before slicing. Serve warm or at room temperature with a green salad.
Nutrition
Notes
If the custard runs toward the edge, fold the pastry up first and pour it in last. The tart keeps covered in the fridge for up to 3 days and reheats well in a 325°F oven.
You might also like our Easy French Apple Tart.
made this for a book club lunch with a big salad and it was perfect. cooking the onions low and slow really makes it
good recipe but some custard leaked out the side. the note about folding first is right, do that
used sour cream bc i couldnt find creme fraiche, came out great. even better cold the next day