The mushrooms start out crowded and glossy in the skillet, then slowly give up their liquid and turn golden. That change is what makes these mushroom and thyme puff pastry tartlets savory without leaving a wet patch in the middle of the pastry. I like them as a small lunch or an easy appetizer; one sheet of pastry makes six tartlets.
The scored border gives each piece a little frame, while Gruyère melts into the mushroom filling and ties it together. I keep the filling inside that frame and let the pastry do its work in a hot oven, where the edges rise and turn crisp. The first bite has buttery layers, browned mushrooms, and a little lift from fresh thyme.
Kitchen Note
Thaw the pastry until it bends without cracking, but keep it cold rather than letting it turn soft and sticky. It’s much easier to unfold and score neatly that way.
Save these mushroom and thyme puff pastry tartlets for a savory bite with crisp, golden edges and a rich Gruyère filling.
Why the Centers Stay Flat While the Borders Puff
These tartlets work because the pastry isn’t asked to rise evenly. A shallow score marks out a border that can lift into a rim, while fork pricks in the center give steam a way out. That contrast makes a shallow well for the mushrooms and cheese instead of one big, domed sheet of pastry.
It’s a small detail, but it changes how the filling sits. Keep the scored line intact rather than cutting through the pastry, or the border can separate from the center as the layers expand. The filling also needs to stay inside the marked area; mushrooms piled over the edge can weigh down the rim and make the finished tartlets harder to handle. Once baked, the border is flaky and distinct, with a tender center that holds its topping.
The Ingredients That Give These Tartlets Their Savory, Buttery Bite
- Puff pastry — Frozen pastry is convenient and gives you distinct, flaky layers. Follow the package thawing directions; pastry that’s still stiff can crack as you unfold it, while pastry that has become sticky is harder to shape cleanly.
- Cremini mushrooms — Their earthy flavor stands up to the cheese and thyme. White button mushrooms are a straightforward substitute with a milder taste. Clean them and slice them evenly so they cook at about the same pace.
- Gruyère — This cheese melts smoothly and brings a nutty, savory note without overwhelming the mushrooms. Swiss cheese is a useful substitute; it melts well, though the flavor is milder.
- Shallot and garlic — Shallot gives the filling a gentle sweetness, while garlic adds a sharper savory note. If you don’t have a shallot, finely chopped yellow onion works, with a slightly more familiar onion flavor. Mince the garlic before it goes into the skillet so it can be stirred in quickly.
- Fresh thyme — Its woodsy aroma suits the mushrooms and keeps the filling from tasting heavy. Pick the leaves from the stems before cooking; dried thyme works too, with the conversion in the FAQ below.
- Olive oil, butter, and egg — Oil and butter cook the filling together, and beaten egg brushed on the border helps it brown. Use unsalted butter so you can control the seasoning in the mushroom mixture.
How to Get Crisp, Golden Tartlets Without a Soggy Center
Brown the mushrooms until the skillet is dry
Heat the olive oil and butter in a 12-inch skillet over medium-high heat, then cook the chopped shallot for 1 minute. Add the sliced mushrooms with the kosher salt and black pepper, and cook for 8 to 10 minutes, stirring occasionally. The mushrooms first release liquid; keep cooking until they’re browned and the liquid has evaporated. Stir in the garlic and thyme for 30 seconds, then set the filling aside to cool for 5 minutes.
Shape the pastry into six framed rectangles
Heat the oven to 400°F and line a 13×18-inch rimmed baking sheet with parchment paper. Unfold the pastry on a lightly floured surface and cut it into six equal rectangles. Score a 1/2-inch border around each rectangle without cutting all the way through, then prick the center several times with a fork. Those fork marks help the middle stay lower than the rim.
Fill the centers and brush the borders
Arrange the pastry rectangles on the lined baking sheet, leaving a little room between them. Brush the borders with beaten egg, then divide the Gruyère and mushroom mixture among the centers. Keep the filling within the scored lines so it doesn’t interfere with the edges as they puff. If the topping is mounded over a border, tuck it back toward the middle before baking.
Bake until the pastry is golden
Bake for 18 to 22 minutes, until the pastry has puffed and turned golden brown. The edges should look crisp, not pale, and the cheese should be melted among the mushrooms. Let the tartlets rest on the baking sheet for 5 minutes before serving; the short rest makes them easier to lift and gives the pastry a moment to settle.
Three Easy Ways to Adapt These Mushroom Tartlets
Make them dairy-free
Use dairy-free puff pastry, replace the butter with a dairy-free butter alternative, and use a dairy-free grated cheese. The filling will still be savory, though it won’t have quite the same nutty, creamy finish as Gruyère.
Use gluten-free puff pastry
Choose a gluten-free puff pastry sheet and dust the work surface with gluten-free flour instead of wheat flour. Follow that pastry’s package directions for thawing and handling; the finished tartlets may have a slightly different rise, but the mushroom and cheese filling stays the same.
Add a little heat
Stir a pinch of red pepper flakes into the skillet along with the garlic and thyme. The heat adds a gentle kick behind the earthy mushrooms without changing the pastry method.
Storage and Reheating
- Refrigerator: Store cooled leftovers in an airtight container for up to 3 days. The pastry softens in the refrigerator.
- Freezer: Freeze fully cooled tartlets in a single layer until solid, then transfer them to an airtight container for up to 2 months. Thaw overnight in the refrigerator before reheating.
- Reheating: Warm in a 350°F oven for 8 to 10 minutes, until crisp and heated through. The microwave is quicker but softens the pastry.
Questions That Come Up When Making These Tartlets
Mushroom and Thyme Puff Pastry Tartlets
Ingredients
Equipment
Method
- Thaw the puff pastry according to package directions until pliable but still cold.
- Heat the oven to 400°F.
- Line a 13x18-inch rimmed baking sheet with parchment paper.
- Heat the olive oil and butter in a 12-inch skillet over medium-high heat.
- Add the shallot and cook for 1 minute.
- Add the mushrooms, salt, and pepper and cook for 8 to 10 minutes, stirring occasionally, until browned and no liquid remains.
- Stir in the garlic and thyme for 30 seconds.
- Set the filling aside to cool for 5 minutes.
- Unfold the pastry on a lightly floured surface.
- Cut the pastry into 6 equal rectangles.
- Score a 1/2-inch border around each rectangle without cutting all the way through.
- Prick the centers several times with a fork.
- Arrange the pastry rectangles on the prepared baking sheet.
- Brush the borders with the beaten egg.
- Divide the Gruyère and mushroom mixture among the centers, keeping the filling inside the scored borders.
- Bake for 18 to 22 minutes, until the pastry is puffed and golden brown.
- Let the tartlets rest on the baking sheet for 5 minutes before serving.
