Chicken Pot Pie on a Sheet Pan

Ingredients:

• 3 tablespoons unsalted butter
• 2 tsp fresh thyme leaves, chopped
• 1/3 cup premium flour + extra for work
• 3 cups lightly salted chicken broth
• 1 grilled chicken, discard the skin, chop the meat (about 3 tbsp.)
• 400 g frozen pearl onions, thawed
• 2 large carrots, cut into thin half-moon slices
• 2 stalks of celery, finely diced
• 2 packages of 500 g puff pastry (4 sheets)
• 1 large egg, beaten with a little water

Preparation:

1. Preheat oven to 200°C and spray a 45x32cm baking pan with cooking spray.
2. In a small saucepan over medium heat, melt the butter with the thyme. Add the flour and cook, stirring, until the mixture reaches the consistency of sand, about 1 minute. Pour in the chicken broth, whisking constantly until smooth. Stir in 2 teaspoons of salt and a pinch of freshly ground black pepper and bring to a boil. Reduce the heat and simmer until the flour thickens, about 10 minutes.
3. Meanwhile, place the shredded chicken, onion, carrot, and celery on the prepared baking sheet and toss to combine; set aside.
4. On a lightly floured work surface, stack two sheets of puff pastry. Roll out into a 37 x 37 cm square. Cut the dough into 2.5 cm wide strips, making 15 strips in total. Repeat with the remaining two sheets of puff pastry.
5. Pour the sauce over the chicken mixture on the baking sheet. Lay the strips of dough crosswise over the filling, overlapping slightly to cover most of the filling. Trim any excess dough hanging off the baking sheet. Brush the dough with the egg wash.
6. Bake until richly golden brown, 35-40 minutes.