Quick Recipe Version (TL;DR)
Quick Ingredients
- 1 sheet (about 250 g) puff pastry, thawed (if frozen)
- 1 large egg + 1 tbsp water (egg wash)
- 2 tbsp olive oil
- 4 tbsp (56 g) unsalted butter, divided
- 1 1/2 lb (680 g) mushrooms (cremini or a mix), sliced
- 2 large leeks (about 500 g whole), cleaned and thinly sliced (about 3 cups/270 g)
- 3 cloves garlic, finely chopped
- 2 tbsp all-purpose flour
- 1/2 cup (120 ml) dry white wine
- 1 cup (240 ml) low-sodium vegetable stock
- 1/2 cup (120 ml) heavy cream
- 1 tbsp Dijon mustard
- 1 tbsp fresh thyme leaves (or 1 tsp dried thyme)
- 1 tbsp fresh parsley, chopped (optional)
- 1 1/4 tsp kosher salt, plus more to taste
- 1/2 tsp black pepper, plus more to taste
Do This
- 1) Heat oven to 400°F (200°C). Set a 9-inch (23 cm) pie dish on a baking sheet.
- 2) Brown mushrooms in oil + 2 tbsp butter over medium-high heat, 10–12 minutes. Season and set aside.
- 3) Soften leeks in remaining 2 tbsp butter, 6–8 minutes. Add garlic and thyme for 30 seconds.
- 4) Stir in flour for 1 minute, then whisk in wine. Simmer 2 minutes; add stock and simmer 3–5 minutes.
- 5) Stir in cream + Dijon + mushrooms; simmer 2–3 minutes until thick. Cool 10 minutes in the dish.
- 6) Top with puff pastry, crimp edges, cut 4 vents, brush with egg wash.
- 7) Bake 25–30 minutes until deeply golden and bubbling. Rest 10 minutes, then serve.
Why You’ll Love This Recipe
- Big, earthy flavor: deeply browned mushrooms and sweet leeks taste rich and cozy.
- Silky, not soupy: the white wine-thyme sauce bakes up creamy and thick.
- Pastry-lid shortcut: all the pie satisfaction with less fuss than a double crust.
- Dinner-party friendly: it looks impressive, but the steps are straightforward.
Grocery List
- Produce: mushrooms (1 1/2 lb / 680 g), 2 large leeks, garlic, fresh thyme (or dried), fresh parsley (optional)
- Dairy: unsalted butter, heavy cream, 1 large egg
- Pantry: puff pastry (1 sheet), olive oil, all-purpose flour, dry white wine, low-sodium vegetable stock, Dijon mustard, kosher salt, black pepper
Full Ingredients
Filling (Mushrooms, Leeks & Creamy White Wine-Thyme Sauce)
- 2 tbsp olive oil
- 4 tbsp (56 g) unsalted butter, divided
- 1 1/2 lb (680 g) mushrooms (cremini, button, or a mix), sliced 1/4-inch (6 mm) thick
- 2 large leeks (about 500 g whole), cleaned well and thinly sliced (about 3 cups / 270 g)
- 3 cloves garlic, finely chopped
- 1 tbsp fresh thyme leaves (or 1 tsp dried thyme)
- 2 tbsp all-purpose flour
- 1/2 cup (120 ml) dry white wine (Sauvignon Blanc or Pinot Grigio works well)
- 1 cup (240 ml) low-sodium vegetable stock
- 1/2 cup (120 ml) heavy cream
- 1 tbsp Dijon mustard
- 1 1/4 tsp kosher salt, plus more to taste
- 1/2 tsp freshly ground black pepper, plus more to taste
- 1 tbsp chopped fresh parsley (optional, for freshness)
Pastry Lid & Finishing
- 1 sheet puff pastry (about 250 g), thawed if frozen
- 1 large egg
- 1 tbsp water
Step-by-Step Instructions
Step 1: Prep the oven, pan, and ingredients
Arrange a rack in the middle of the oven and preheat to 400°F (200°C). Set a 9-inch (23 cm) pie dish on a rimmed baking sheet (this catches any bubbly sauce and makes it easier to move in and out of the oven).
Clean the leeks well: slice off the dark green tops, halve the white and light-green parts lengthwise, rinse between the layers, then thinly slice. Slice the mushrooms and chop the garlic. If using frozen puff pastry, make sure it is thawed enough to roll without cracking.
Step 2: Brown the mushrooms for maximum flavor
Heat 2 tbsp olive oil and 2 tbsp (28 g) butter in a large skillet (12-inch/30 cm is ideal) over medium-high heat.
Add the mushrooms in an even layer. Let them sit undisturbed for 3 minutes to start browning, then stir and continue cooking until most moisture has cooked off and the mushrooms are deeply golden, 10–12 minutes total. Sprinkle with about 1/2 tsp of the salt and a pinch of pepper. Transfer mushrooms to a bowl.
Step 3: Cook the leeks until silky
Reduce heat to medium. Add the remaining 2 tbsp (28 g) butter to the skillet.
Add the sliced leeks and cook, stirring often, until soft and glossy but not browned, 6–8 minutes. Add the garlic and thyme and cook until fragrant, 30 seconds.
Step 4: Build the white wine-thyme sauce
Sprinkle 2 tbsp flour over the leeks and stir constantly for 1 minute to cook off the raw flour taste.
Pour in the 1/2 cup (120 ml) white wine and stir, scraping up any browned bits from the pan. Simmer until the wine reduces slightly, 2 minutes.
Slowly pour in the 1 cup (240 ml) vegetable stock, stirring as you go. Bring to a gentle simmer and cook until the mixture thickens to a saucy consistency, 3–5 minutes.
Step 5: Finish the filling and cool it slightly
Stir in the 1/2 cup (120 ml) heavy cream and 1 tbsp Dijon mustard. Add the browned mushrooms (and any juices in the bowl) back to the skillet. Simmer gently until the filling looks creamy and thick (it should coat a spoon), 2–3 minutes.
Season with the remaining salt and pepper (start with the remaining 3/4 tsp kosher salt and adjust to taste). Stir in parsley, if using.
Spoon the hot filling into the 9-inch (23 cm) pie dish and spread it into an even layer. Let it cool for 10 minutes so the pastry doesn’t melt as soon as it touches the filling.
Step 6: Add the puff pastry lid and vent
On a lightly floured surface, roll the puff pastry to about 11 inches (28 cm) across (just large enough to drape over the dish with a little overhang). Lay it over the pie dish.
Trim excess pastry so you have about a 1/2-inch (1.3 cm) overhang. Tuck the edge under slightly and crimp with a fork or your fingers to seal.
Cut 4 small slits in the top for steam vents.
Step 7: Egg wash and bake until bronzed
Whisk together 1 large egg and 1 tbsp water. Brush a thin, even layer over the pastry (you won’t necessarily use it all).
Bake at 400°F (200°C) until the pastry is deeply golden and the filling is bubbling at the edges, 25–30 minutes.
Let the pie rest for 10 minutes before slicing. This helps the sauce set so you get neat, satisfying servings.
Pro Tips
- Don’t crowd the mushrooms: If your skillet is small, brown them in two batches. Crowding steams them and you lose that deep, earthy flavor.
- Leek cleaning matters: Grit hides between layers. Rinse thoroughly after slicing, then pat dry so they sauté instead of steam.
- Control thickness: If the sauce seems thin before baking, simmer it 1–2 minutes longer. It should look like a thick chowder, not a broth.
- Cool before topping: A short 10-minute cool-down keeps the puff pastry from slipping and melting into the filling.
- Go for color: Bake until properly bronzed; pale puff pastry tastes underdone even if it’s technically baked.
Variations
- Add cheese: Stir in 1/2 cup (50 g) grated Gruyère or Parmesan right after the cream for a deeper savory note.
- Make it heartier: Add 1 cup (150 g) thawed frozen peas or 2 cups (60 g) baby spinach (stir in at the end until wilted).
- Swap the herbs: Use 1 tsp chopped fresh rosemary instead of thyme for a woodsy flavor (go easy; rosemary is strong).
Storage & Make-Ahead
Refrigerate: Cool leftovers completely, then cover and refrigerate for up to 3 days.
Reheat: Warm in a 350°F (175°C) oven for 20–25 minutes (this helps re-crisp the pastry). Microwave reheating works in a pinch, but the pastry will soften.
Make-ahead option: Prepare the filling up to 24 hours ahead and refrigerate in an airtight container. When ready to bake, rewarm the filling on the stove just until steamy (so it isn’t ice-cold), transfer to the pie dish, top with pastry, then bake as directed.
Nutrition (per serving)
Approximate, based on 6 servings: 520 calories, 10 g protein, 42 g carbohydrates, 34 g fat, 4 g fiber, 680 mg sodium.
