Step 1: Prepare the Base
Preheat your oven to 425°F (220°C).
Heat olive oil in your Dutch oven over medium-high heat.
Season chicken pieces with salt and pepper, then add to the hot oil.
Cook chicken for 5-7 minutes until lightly browned on all sides. Remove and set aside.
Step 2: Build the Vegetable Foundation
Add diced onion to the same pot and cook for 3-4 minutes until softened.
Add carrots and celery and cook for another 5 minutes, stirring occasionally.
Add mushrooms and cook until they release their moisture, about 4-5 minutes.
Stir in minced garlic and cook for 1 minute until fragrant.
Step 3: Create the Creamy Sauce
Add butter to the pot and let it melt completely.
Sprinkle flour over the vegetables and stir constantly for 2 minutes to cook out the raw flour taste.
Gradually add chicken broth while stirring constantly to prevent lumps.
Bring to a simmer and cook until the sauce thickens, about 3-4 minutes.
Stir in heavy cream, thyme, and sage. Season with salt and pepper to taste.
Step 4: Combine and Top
Return chicken to the pot along with frozen peas and corn.
Stir gently to combine all ingredients evenly.
Roll out puff pastry slightly larger than your pot opening.
Place pastry over the pot, trimming excess and crimping edges to seal.
Brush with beaten egg for a golden finish.
Cut 4-5 small vents in the pastry to allow steam to escape.
Step 5: Bake to Perfection
Bake for 25-30 minutes until the pastry is golden brown and the filling is bubbling.
Let rest for 5-10 minutes before serving.
Garnish with fresh parsley and serve hot.