As a pastry chef, I developed this savory tart to highlight caramelization’s magic. A crisp, buttery crust holds a luscious layer of slowly cooked onions and nutty Gruyère. Fresh thyme adds herbal nuance. It’s an elegant starter or light meal when served alongside a crisp green salad.
Ingredients
For the Crust:
1⅓ cups all-purpose flour
½ teaspoon salt
8 tablespoons cold unsalted butter, cubed
3–4 tablespoons ice water
For the Filling:
3 large onions, thinly sliced
2 tablespoons olive oil
1 tablespoon unsalted butter
1 teaspoon sugar
Salt and pepper
1 cup grated Gruyère cheese
1 teaspoon fresh thyme leaves, plus extra for garnish
2 large eggs
½ cup heavy cream
Instructions
Make the Crust
Pulse flour and salt with butter in a food processor until pea-sized crumbs form.
Add ice water, 1 tablespoon at a time, until dough just comes together. Flatten into a disk; chill 30 minutes.
Caramelize Onions
Heat oil and butter in a skillet over medium-low heat. Add onions, sugar, salt; cook 30–35 minutes, stirring occasionally, until deep golden.
Blind Bake Crust
Preheat oven to 375°F (190°C). Roll dough into a 9″ tart pan; trim edges. Line with parchment, fill with pie weights.
Bake 15 minutes, remove weights and parchment; bake 5 more until lightly golden. Reduce oven to 350°F (175°C).
Assemble & Bake
Spread onions evenly in crust. Sprinkle Gruyère and thyme. Whisk eggs and cream; pour over.
Bake 25–30 minutes until filling is set and top is lightly browned.
Serve
Let rest 10 minutes, then slice. Garnish with extra thyme and serve warm.
Pro Tips
Even Caramelization: Stir onions gently; scrape any fond to incorporate deep flavor.
Cheese Swap: Substitute Comté or Emmental for similar nuttiness.
Make-Ahead: Dough and onions can be prepared a day ahead; assemble before baking.
Conclusion
This caramelized onion and Gruyère tart with thyme encapsulates French pastry expertise in an approachable recipe.