Quick Recipe Version (TL;DR)
Quick Ingredients
- 1 sheet all-butter puff pastry (8.6 oz/245 g), thawed
- 1 large egg + 1 tbsp milk (egg wash)
- 1.75 lb (800 g) boneless, skinless chicken thighs, 1-inch pieces
- 1.5 tsp kosher salt, divided; 3/4 tsp black pepper, divided
- 1 tbsp olive oil; 2 tbsp unsalted butter
- 2 medium leeks, white/light green parts, thinly sliced (about 3 cups)
- 12 oz (340 g) cremini mushrooms, thick-sliced
- 3 garlic cloves, minced
- 3 tbsp all-purpose flour
- 1/2 cup (120 ml) dry white wine
- 1 1/4 cups (300 ml) low-sodium chicken stock
- 3/4 cup (180 ml) heavy cream
- 2 tsp Dijon mustard
- 2 tbsp chopped fresh tarragon; 1 tsp fresh thyme leaves
- 1 tsp lemon juice + 1/2 tsp zest
- 1/2 cup frozen peas (optional)
Do This
- 1. Heat oven to 400°F (200°C). Place a rimmed baking sheet on the middle rack to preheat. Whisk egg and milk.
- 2. Season chicken with 1 tsp salt and 1/2 tsp pepper. Sear in olive oil over medium-high in a large skillet until lightly browned, 5–7 minutes. Transfer to a bowl.
- 3. In same skillet, melt butter. Cook leeks 4 minutes. Add mushrooms; cook until browned and their liquid evaporates, 6–8 minutes. Stir in garlic 30 seconds.
- 4. Sprinkle in flour; cook 1 minute. Deglaze with wine; simmer 1 minute. Whisk in stock; simmer until thickened, 3–4 minutes.
- 5. Stir in cream, Dijon, thyme, tarragon, lemon juice/zest. Return chicken and any juices; simmer 3 minutes. Add peas (optional). Season to taste.
- 6. Spoon filling into a 2-qt (2 L) baking dish. Lay pastry over top, trim, crimp, and cut 3–4 vents. Brush with egg wash.
- 7. Bake on hot sheet 25–30 minutes until towering and deeply golden. Rest 10 minutes. Garnish with tarragon and serve.
Why You’ll Love This Recipe
- Buttery puff-pastry lid rises tall and bakes a deep golden brown with crisp, flaky layers.
- Comforting, creamy tarragon sauce cloaks tender chicken, leeks, and mushrooms.
- Smart use of a preheated sheet pan ensures a thoroughly crisp pastry base and edges.
- Make-ahead friendly filling that reheats beautifully for weeknights or guests.
Grocery List
- Produce: 2 leeks, 12 oz cremini mushrooms, 3 garlic cloves, fresh tarragon, fresh thyme, 1 lemon
- Dairy: All-butter puff pastry (1 sheet), heavy cream, unsalted butter, 1 large egg, milk
- Pantry: Boneless skinless chicken thighs, olive oil, all-purpose flour, dry white wine, low-sodium chicken stock, Dijon mustard, kosher salt, black pepper, frozen peas (optional)
Full Ingredients
For the Filling
- 1.75 lb (800 g) boneless, skinless chicken thighs, cut into 1-inch pieces
- 1 tsp kosher salt, plus more to taste
- 1/2 tsp freshly ground black pepper, plus more to taste
- 1 tbsp olive oil
- 2 tbsp unsalted butter
- 2 medium leeks, white and light green parts only, thinly sliced (about 3 cups)
- 12 oz (340 g) cremini mushrooms, thick-sliced
- 3 garlic cloves, minced
- 3 tbsp all-purpose flour
- 1/2 cup (120 ml) dry white wine
- 1 1/4 cups (300 ml) low-sodium chicken stock
- 3/4 cup (180 ml) heavy cream
- 2 tsp Dijon mustard
- 2 tbsp finely chopped fresh tarragon, plus extra leaves for garnish
- 1 tsp fresh thyme leaves (or 1/2 tsp dried thyme)
- 1 tsp fresh lemon juice + 1/2 tsp finely grated lemon zest
- 1/2 cup frozen peas (optional)
For the Pastry Lid
- 1 sheet all-butter puff pastry (8.6 oz/245 g), thawed but cold
- 1 large egg, beaten with 1 tbsp milk (egg wash)
Equipment
- 12-inch (30 cm) skillet or sauté pan
- 2-qt (2 L) baking dish (about 9-inch square or similar)
- Rimmed baking sheet (for preheating)
- Rolling pin (optional, for sizing pastry)
- Pastry brush and sharp knife
Step-by-Step Instructions
Step 1: Heat the oven and prep the pastry
Position a rack in the center of the oven and place a rimmed baking sheet on it. Heat the oven to 400°F (200°C). Keep the puff pastry in the fridge until needed so it stays cold. Whisk the egg with 1 tbsp milk for the egg wash and set aside.
Step 2: Sear the chicken
Pat the chicken dry and season with 1 tsp kosher salt and 1/2 tsp pepper. Heat the olive oil in a large skillet over medium-high. Add the chicken in a single layer and sear, stirring once or twice, until lightly browned but not fully cooked through, 5–7 minutes. Transfer to a bowl with any juices.
Step 3: Soften leeks and brown mushrooms
Reduce heat to medium and add the butter. Stir in the leeks with a pinch of salt and cook until softened, 4–5 minutes, stirring occasionally. Add the mushrooms and cook until they release their liquid and turn golden around the edges, 6–8 minutes. Stir in the garlic and cook 30 seconds until fragrant.
Step 4: Make the roux and deglaze
Sprinkle the flour evenly over the vegetables and cook, stirring, for 1 minute to remove the raw taste. Pour in the wine and stir, scraping up any browned bits. Let it simmer 1 minute. Gradually whisk in the chicken stock and bring to a gentle simmer; cook until the sauce thickens enough to coat a spoon, 3–4 minutes.
Step 5: Finish the creamy tarragon sauce
Stir in the heavy cream, Dijon, thyme, tarragon, lemon juice, and zest. Return the chicken and any collected juices to the pan. Simmer gently until the chicken is just cooked through and the sauce is silky and thick but spoonable, 3–4 minutes. Add peas if using. Taste and adjust with salt and pepper as needed. Take off the heat and let the filling cool for 5–10 minutes to slightly thicken.
Step 6: Assemble the pie
Spoon the filling into a 2-qt (2 L) baking dish. Lightly roll the cold puff pastry if needed to fit with a small overhang. Lay it over the filling, trim excess to a 1/2-inch (1 cm) border, then fold and crimp against the dish rim. Cut 3–4 vents on top to release steam. Brush evenly with egg wash.
Step 7: Bake until towering and deeply golden
Set the dish on the preheated baking sheet and bake at 400°F (200°C) until the pastry is dramatically puffed, deeply golden, and the filling bubbles through the vents, 25–30 minutes. Rotate the dish once halfway for even color if needed.
Step 8: Rest and serve
Let the pie rest 10 minutes to settle. Garnish with extra tarragon leaves, crack on a little black pepper if you like, and serve hot.
Pro Tips
- Keep the pastry cold and the filling hot but not boiling; warm filling and cold dough yield the best rise and flake.
- Preheating a baking sheet under the dish promotes rapid heat transfer for ultra-crisp pastry edges and base contact.
- Cook mushrooms until their moisture fully evaporates before adding flour; this prevents a watery sauce.
- The sauce should be thick enough to coat a spoon before adding the pastry. If it’s thin, simmer 2–3 minutes more.
- Score and vent the pastry to release steam and prevent sogginess while encouraging a high, layered lift.
Variations
- Cider and Crème Fraîche: Swap the white wine for dry hard cider and replace half the cream with crème fraîche for a tangy finish.
- Bacon-Leek: Render 4 oz (115 g) diced smoked bacon first; use the drippings with 1 tbsp butter to cook the leeks. Proceed as written.
- Individual Pies: Divide filling among 4–6 oven-safe bowls and top each with pastry. Bake 18–22 minutes until puffed and golden.
Storage & Make-Ahead
Refrigerate leftovers in an airtight container for up to 3 days. Reheat at 350°F (175°C) for 15–20 minutes until hot and crisp. The filling can be made up to 2 days ahead; cool completely and refrigerate. For freezing, cool the filling and freeze up to 3 months; thaw overnight in the fridge before assembling with fresh pastry. You can also assemble the pie and freeze unbaked; bake from frozen at 400°F (200°C) for 35–45 minutes, shielding edges if browning too fast.
Nutrition (per serving)
Approx. 750 calories; 29 g protein; 33 g carbohydrates; 50 g fat; 2 g fiber; 800 mg sodium. Nutrition will vary with pastry brand and optional peas.
