Instructions
- Prep and blind bake the crust. Preheat oven to 375°F (190°C). Roll out your pie crust and press it into a 9-inch tart pan. Trim excess, leaving a ½-inch overhang. Fold under and crimp edges. Prick the bottom all over with a fork. Line with parchment paper and fill with pie weights. Bake for 15 minutes. Remove parchment and weights, brush with beaten egg white, and bake 5 more minutes until lightly golden. Set aside and reduce oven to 325°F (165°C).
- Sauté the mushrooms (the key step!). Clean mushrooms with a damp paper towel — don't rinse them, as they'll absorb water. Remove any tough stems (especially from shiitakes). Slice into ¼-inch thick pieces. Heat butter and olive oil in a large skillet over medium-high heat until shimmering. Add mushrooms in a single layer — work in batches if needed; crowding will make them steam instead of brown. Cook without stirring for 3-4 minutes until deep golden brown on one side. Flip and cook 2-3 minutes more. Season with salt and pepper. Transfer to a bowl.
- Sauté aromatics and deglaze. Reduce heat to medium. In the same skillet (don't wipe it clean — those browned bits are flavor gold), add diced shallots and cook until softened and translucent, about 3 minutes. Add minced garlic and cook 1 minute more until fragrant. Add white wine or sherry and scrape up all the browned bits from the bottom of the pan. Cook until the liquid almost completely evaporates, about 2 minutes. Add fresh thyme leaves and return the mushrooms to the pan. Toss to combine. Let cool slightly.
- Make the custard. In a large bowl, whisk the eggs until smooth. Add heavy cream, whole milk, nutmeg, salt, and pepper. If using truffle oil, add it now — just 1 teaspoon adds incredible depth without overpowering. Whisk until completely combined and smooth.
- Assemble the quiche. Spread the mushroom mixture evenly over the bottom of the blind-baked crust. Sprinkle half of the grated Gruyère and half of the Parmesan over the mushrooms. Pour the custard mixture slowly and evenly over the filling. The liquid should come to within ¼ inch of the top. Sprinkle the remaining Gruyère and Parmesan over the surface.
- Bake to perfection. Place on a baking sheet and bake at 325°F for 35-40 minutes. The quiche is done when the edges are set but the center still has a very slight jiggle when gently shaken. The top should be golden brown with lightly browned, melted cheese.
- Rest before serving. Let the quiche cool on a wire rack for at least 15 minutes before slicing. This allows the custard to fully set and the flavors to develop. Serve warm or at room temperature. Drizzle with an extra tiny bit of truffle oil just before serving if you're feeling luxurious.
Chef's Tips for Success
- Mix your mushrooms — combining varieties creates complex flavor. Cremini add earthiness, shiitake bring umami, oyster contribute delicate texture.
- Don't crowd the pan — mushrooms release water when heated. If the pan is crowded, they'll steam and turn rubbery instead of caramelizing. Cook in batches if needed.
- Get good color — deeply browned mushrooms have vastly more flavor than pale ones. Resist the urge to stir constantly.
- The wine deglazing is crucial — it picks up all the caramelized bits and adds depth. Don't skip this step.
- Truffle oil goes a long way — a little is luxurious, too much is overwhelming. Start with 1 teaspoon, taste, and add a few more drops if desired.
Recipe Variations
- Add caramelized onions: Layer in ½ cup deeply caramelized onions for extra sweetness.
- Make it luxurious: Fold in 2 tablespoons crème fraîche or mascarpone to the custard.
- Add greens: Wilt 2 cups fresh spinach or arugula with the mushrooms for color and nutrition.
- Cheese swap: Try aged Comté, fontina, or a mix of mozzarella and Parmesan.
- Herb variation: Use fresh rosemary or a combination of thyme and tarragon.
Storage & Reheating
Refrigerate: Cover tightly and store up to 4 days. The mushroom flavor actually deepens overnight.
Freeze: Wrap cooled quiche in plastic wrap, then foil. Freeze up to 3 months. The mushrooms hold their texture beautifully.
Reheat: From fridge: 350°F for 15 minutes. From frozen: 325°F for 35-40 minutes, covered with foil. Add a fresh drizzle of truffle oil after reheating.