01 -
Preheat your oven to 400°F (200°C). Lightly grease six 6-ounce ramekins.
02 -
Roll out the thawed puff pastry on a lightly floured surface to about 1/8 inch thickness. Cut into rounds slightly larger than the ramekins.
03 -
In a large skillet over medium heat, melt the butter and add the onions. Cook until translucent, about 4 minutes.
04 -
Add the garlic and mushrooms to the skillet. Cook, stirring occasionally, until the mushrooms are golden brown and have released their moisture, about 8-10 minutes.
05 -
Stir in the thyme leaves and flour. Cook for another 2 minutes to remove the raw flour taste.
06 -
Gradually pour in the vegetable broth, stirring continuously to avoid lumps. Bring the mixture to a simmer.
07 -
Add the heavy cream and reduce the heat. Cook until the sauce thickens, about 5 minutes.
08 -
Season the mixture with salt and freshly ground black pepper to taste.
09 -
Divide the mushroom mixture evenly among the prepared ramekins. Sprinkle Gruyère cheese generously over the top.
10 -
Place a puff pastry round over each ramekin, pressing the edges gently to seal. Brush the tops with the beaten egg.
11 -
Place the ramekins on a baking sheet and bake for 15-20 minutes, or until the puff pastry is golden and puffed.
12 -
Allow to cool slightly for 10 minutes before serving.