This mushroom galette pairs crisp, buttery pastry with a savory filling of browned cremini mushrooms, sweet onion, thyme, Dijon, and nutty Gruyère. It is a relaxed dinner centerpiece that slices neatly after a short rest. The key is to cook off the mushrooms’ moisture and cool the filling before it meets the pastry.
What makes this galette work
A galette is folded free-form, so there is no pie dish to line. Store-bought puff pastry keeps the method practical, while a thin swipe of Dijon beneath the cheese adds savoriness and helps create a barrier between the filling and crust. The mushrooms need enough pan space to brown; if the skillet is crowded, they steam and release liquid that can soften the bottom.
Ingredients and useful choices
Use one thawed but still-cold sheet of puff pastry, cremini mushrooms, a yellow onion, garlic, fresh thyme, olive oil, butter, Dijon mustard, Gruyère, an egg for the wash, and parsley to finish. Cremini give a deeper flavor than white button mushrooms, but either works. Wipe mushrooms with a damp towel and trim the dry ends; soaking them adds water. Gruyère melts smoothly, while Swiss cheese is a reasonable substitute. If your pastry sheet is smaller than about 10 by 14 inches, use a little less filling so the folded edge can close comfortably.
Brown the filling before assembling
Cook the onion in olive oil and butter over medium heat until soft and lightly golden, about 6–8 minutes. Add the mushrooms in an even layer and leave them undisturbed for a couple of minutes before stirring. Continue cooking until their liquid has evaporated and the edges are browned, usually 8–10 minutes. Stir in garlic, thyme, salt, and pepper for the final minute. Spread the mixture on a plate and let it cool for at least 10 minutes; warm filling can melt the pastry before it bakes.
Fold, bake, and serve
Heat the oven to 400°F (200°C) and line a rimmed baking sheet with parchment. On a lightly floured surface, roll the cold pastry into a rectangle about 10 by 14 inches. Transfer it to the sheet, spread Dijon over the center while leaving a 2-inch border, and scatter on the Gruyère. Spoon the cooled mushroom mixture over the cheese. Fold the pastry border over the filling in overlapping sections, leaving the middle open. Brush the pastry with beaten egg.
Bake for 25–30 minutes, until the pastry is deeply golden on top and crisp underneath. If the top colors early, loosely tent it with foil for the last few minutes. Rest the galette for 10 minutes before slicing so the cheese settles. Finish with parsley and serve with a simply dressed green salad or roasted vegetables. For another mushroom-forward dinner, try our creamy mushroom risotto, or browse more dinner recipes.
Make-ahead and leftovers
The mushroom filling can be cooked up to two days ahead and refrigerated; bring it close to room temperature before assembling. Keep pastry cold until rolling. Refrigerate leftover slices in a covered container for up to 3 days. Reheat on a baking sheet at 350°F (175°C) for 8–12 minutes, until the pastry is hot and crisp again; a microwave warms it quickly but softens the crust.
Nutrition estimate
Approximate nutrition per slice (one-sixth of the galette) is calculated from common ingredient data and can vary with puff pastry and cheese brands. It is an estimate, not a laboratory analysis.
| Nutrient | Estimated amount per slice |
|---|---|
| Calories | 390 kcal |
| Carbohydrates | 34 g |
| Protein | 11 g |
| Total fat | 26 g |
| Saturated fat | 6 g |
| Fiber | 2 g |
| Total sugars | 3 g |
| Sodium | 520 mg |
Savory Mushroom and Gruyère Galette with Thyme
Ingredients
Method
- Heat the oven to 400°F (200°C). Line a rimmed baking sheet with parchment. Keep the puff pastry cold until you are ready to assemble.
- Warm the olive oil and butter in a wide skillet over medium heat. Add the onion and cook for 6 to 8 minutes, stirring, until soft and lightly golden.
- Add the mushrooms in an even layer. Cook for 8 to 10 minutes, stirring only occasionally, until their released liquid has evaporated and the edges are browned. Stir in the garlic, thyme, salt, and pepper for the final 30 seconds. Transfer the filling to a plate and cool for 10 minutes; a hot filling can soften the pastry.
- On a lightly floured surface, roll the cold pastry into a rectangle about 10 by 14 inches. Move it to the prepared sheet. Lightly score a 1-inch border without cutting through, then prick the center with a fork. Spread Dijon inside the border and scatter over the Gruyère.
- Spoon the cooled mushroom mixture over the cheese. Fold and pleat the pastry border around the filling. Brush the edge with the egg wash.
- Bake for 25 to 30 minutes, rotating the pan once, until the pastry is puffed and deep golden underneath and around the edges. Rest for 10 minutes, then finish with parsley and slice. If the center still looks pale, bake 3 to 5 minutes longer.
