Caramelized Onion and Gruyère Galette

By AislePrompt Editorial · Published 2026-06-19 · Updated 2026-06-19

A rustic free-form tart featuring sweet caramelized onions and melted Gruyère cheese in a buttery crust. This French-inspired vegetarian recipe, ready in about 85 minutes, pairs all-purpose flour, unsalted butter, cold and cubed, ice water for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 320 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 1 1/4 cups all-purpose flour
• 6 tbsp unsalted butter, cold and cubed
• 3-4 tbsp ice water
• 2 medium large onions, thinly sliced
• 2 tbsp olive oil
• 1 tsp salt
• 1/2 tsp black pepper
• 1 tsp fresh thyme leaves
• 1 cup Gruyère cheese, shredded
• 1 egg, beaten (for egg wash)

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Instructions

1. Step 1: To make the dough, combine 1 1/4 cups all-purpose flour and 6 tbsp cold cubed unsalted butter in a bowl. Use your fingers or a pastry cutter to work the butter into the flour until mixture resembles coarse crumbs.
2. Step 2: Add 3-4 tbsp ice water, 1 tbsp at a time, mixing gently until the dough comes together. Form into a disk, wrap in plastic, and chill for 30 minutes.
3. Step 3: Meanwhile, heat 2 tbsp olive oil in a skillet over medium heat. Add 2 thinly sliced medium onions and 1 tsp salt. Cook slowly, stirring occasionally, for 25-30 minutes until onions are deeply golden and caramelized.
4. Step 4: Remove onions from heat and season with 1/2 tsp black pepper and 1 tsp fresh thyme leaves. Let cool.
5. Step 5: Preheat oven to 400°F (200°C). On a lightly floured surface, roll out chilled dough into a 12-inch circle. Transfer to a baking sheet lined with parchment paper.
6. Step 6: Spread the caramelized onions evenly over the dough, leaving a 2-inch border. Sprinkle 1 cup shredded Gruyère cheese over the onions.
7. Step 7: Fold the edges of the dough inward over the filling, pleating as needed. Brush the dough edges with 1 beaten egg.
8. Step 8: Bake for 30-35 minutes until the crust is golden brown and cheese is melted and bubbly. Let cool 5 minutes before slicing and serving.