👨‍🍳 步驟

1. 1

   Preheat your oven to 220°C (425°F). If using puff pastry, lightly roll it out on a floured surface to about 3-4mm thickness. Place it on a baking sheet lined with parchment paper.

   💡 專業提示: Ensure the oven is fully preheated for a crispy crust.
2. 2

   In a skillet, melt butter and olive oil over medium heat. Add the sliced onions and cook until softened and lightly golden, about 5-7 minutes.

   💡 專業提示: Low and slow cooking of onions brings out their sweetness.
3. 3

   Add the minced garlic and sliced mushrooms to the skillet. Cook until the mushrooms have released their liquid and are tender and lightly browned, about 5-8 minutes. Season with salt, pepper, and fresh thyme if using.

   💡 專業提示: Don't overcrowd the pan when cooking mushrooms to ensure they brown rather than steam.
4. 4

   Spread the crème fraîche evenly over the puff pastry, leaving a small border around the edges.

   💡 專業提示: Use the back of a spoon to spread the crème fraîche smoothly.
5. 5

   Distribute the cooked mushroom and onion mixture evenly over the crème fraîche.

   💡 專業提示: Ensure an even distribution for balanced flavor in every bite.
6. 6

   Sprinkle the grated Gruyère cheese over the mushrooms and onions.

   💡 專業提示: Grate the cheese fresh for the best melting consistency.
7. 7

   Bake in the preheated oven for 12-15 minutes, or until the pastry is golden brown and puffed, and the cheese is melted and bubbly.

   💡 專業提示: Keep an eye on the tart to prevent the edges from burning.
8. 8

   Let it cool slightly before slicing and serving. Enjoy hot.

   💡 專業提示: This tart is best served immediately.