French-Inspired Roasted Mushroom and Gruyère Tart

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

How this recipe was made — this recipe was drafted by AislePrompt's AI-assisted pipeline from technique templates and USDA-sourced nutrition data, and published by AislePrompt Editorial — see how AislePrompt recipes are developed and reviewed.

A savory tart with a flaky pastry crust filled with caramelized mushrooms, melted Gruyère cheese, and fresh thyme, perfect for a light dinner or brunch. This French-inspired vegetarian recipe, ready in about 45 minutes, layers puff pastry sheet, unsalted butter, shallots into a dessert worth slowing down for — great for weekend baking, holiday tables, or any time you want a sweet payoff at the end of a meal. Each serving lands at about 420 calories and feeds 4, so it slots into a weekend bake or a special-occasion dessert tray. 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.

Prep: 15 min Cook: 30 min Serves 4 French cuisine 420 cal/serving

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Ingredients

1 (9-inch) sheet, thawed puff pastry sheet
12 oz, sliced mixed mushrooms (cremini, shiitake, button)
2 tbsp unsalted butter
2, finely chopped shallots
1 tbsp fresh thyme leaves
1/2 tsp salt
1/4 tsp black pepper
1 cup shredded Gruyère cheese
1/4 cup heavy cream
1, beaten for egg wash egg

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Instructions

Step 1: Preheat oven to 400°F. Roll out 1 thawed 9-inch puff pastry sheet on a baking sheet lined with parchment paper. Score a 1-inch border around the edges without cutting through.
Step 2: In a large skillet, melt 2 tbsp unsalted butter over medium heat. Add 2 finely chopped shallots and sauté for 2 minutes until translucent. Add 12 oz sliced mixed mushrooms, 1 tbsp fresh thyme leaves, 1/2 tsp salt, and 1/4 tsp black pepper; cook for 8-10 minutes until mushrooms release moisture and become golden brown.
Step 3: Spread the cooked mushroom mixture evenly inside the pastry border. Sprinkle 1 cup shredded Gruyère cheese over the mushrooms. Drizzle 1/4 cup heavy cream evenly on top.
Step 4: Brush the 1-inch pastry border with 1 beaten egg to help it brown. Bake the tart for 20-25 minutes until the crust is puffed and golden and the cheese is melted and bubbling.
Step 5: Let the tart cool for 5 minutes before slicing. Serve warm with a side salad.