Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

Warm a large skillet over medium heat, adding a splash of olive oil and a small knob of butter.

Add sliced shallots with a pinch of salt and cook until soft and light golden, about 5 to 7 minutes.

Add sliced mushrooms and another small pinch of salt. Cook without moving to get some color, then stir and continue until tender, about 8 to 10 minutes.

Stir in minced garlic and thyme for the last minute, then taste and adjust seasoning.

Remove from heat and let cool for a few minutes.

Unfold puff pastry on a lightly floured surface and roll gently to even out creases.

Cut into rectangles or squares and transfer to the parchment-lined sheet.

Score a border about half an inch from the edges without cutting through, then dock centers with a fork.

Spread or crumble the goat cheese inside the border, then spoon the mushroom-shallot mixture over it.

Brush edges with egg wash, then bake for 18 to 22 minutes until puffed and golden.

Cool slightly on the pan before transferring to a rack. Finish with fresh thyme and serve warm or at room temperature.