Ingredients
Scale
- 8 oz. baby bella mushrooms (divided)
- 1 large shallot (coarsely chopped)
- 1 tbsp. vegetable oil
- Kosher salt
- 1 oz. Gruyère cheese (grated)
- 2 tbsp. heavy cream
- 2 tbsp. sour cream or crème fraîche
- 1/2 tsp. cornstarch
- 1/2 tsp. fresh thyme leaves (chopped)
- All-purpose flour (for dusting)
- 1 sheet frozen puff pastry (thawed)
Instructions
- Preheat your oven to 375°F and line two baking sheets with parchment paper. Slice 4 oz of mushrooms into 1/4″ slices and set them aside.
- In a food processor, pulse the shallot and the remaining 4 oz of mushrooms until finely chopped, about 15 times.
- Heat oil in a medium skillet over medium-low heat. Add the shallot mixture and season with salt. Cook until light brown and most of the liquid evaporates, about 15 minutes. Transfer to a bowl and let it cool slightly.
- Add Gruyère, heavy cream, sour cream, cornstarch, and thyme to the mushroom mixture and mix until combined.
- On a lightly floured surface, lay the pastry flat and cut it into 12 (3″) squares. Place 2 slices of reserved mushrooms on parchment on a prepared sheet, top with 1 tbsp. filling, and cover with a pastry square. Press around the edges to enclose. Repeat with the remaining tartlets, spacing them about 2″ apart.
- Bake until the pastry is puffed and golden brown, about 15 to 20 minutes. Let them cool slightly, then invert onto a wire rack to cool completely.
- **Make Ahead:** The filling can be made 3 days ahead and stored in an airtight container in the fridge. Puff pastry squares can be cut a day ahead. Simply place them on a parchment-lined sheet, wrap tightly with plastic wrap, and refrigerate.
- Prep Time: 45 minutes
- Category: Appetizer