Preheat oven to 400°F (200°C). Lightly grease six 6-oz ramekins.

Roll out puff pastry to 1/8-inch thickness and cut circles slightly larger than the ramekins.

In a large skillet, melt butter over medium heat. Add onion and cook until translucent, about 4 minutes.

Add garlic and mushrooms; cook 8–10 minutes until browned and moisture evaporates.

Stir in thyme and flour. Cook 2 minutes, stirring constantly.

Slowly add vegetable broth while stirring to smooth out lumps.

Add heavy cream, reduce heat, and simmer 5 minutes until thickened.

Season with salt and pepper.

Spoon mushroom mixture into ramekins and top with shredded Gruyère.

Cover each with puff pastry, sealing edges gently.

Brush with beaten egg.

Bake 15–20 minutes or until puffed and golden brown.

Cool for 10 minutes before serving.