If you’ve scrolled through TikTok lately, you’ve probably seen the famous upside-down tartlets popping up all over. These simple pastries turn store-bought puff pastry and your favorite sweet or savory filling into delightful bite-sized treats. While some use apples or tomatoes, we’re diving into savory territory with a creamy mushroom-inspired filling.
Here’s the twist: we’re using mushrooms in two ways—sliced and in a rich, cheesy filling. The filling starts with minced mushrooms and shallots, a combo known as duxelles. To give it that mushroom soup vibe, we add Gruyère, heavy cream, and either sour cream or crème fraîche. The tangy dairy balances the richness without curdling in the oven.
When dealing with puff pastry, keep it cool! The layers of cold butter need to melt in the oven to create that flaky texture we love. If the pastry gets too warm, it won’t puff up properly. If you notice it warming up, pop it in the fridge for 10 to 15 minutes to chill before working with it again.
The best part? You can prepare most of this recipe ahead of time. The mushroom filling can be made up to 3 days ahead, and you can cut the puff pastry squares and refrigerate them a day in advance.
Upside-Down Cream Of Mushroom Tartlets
Ingredients
- 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.