Ingredients

• 2 ounces pancetta, chopped
• 1 tbsp olive oil
• 1 leek, trimmed and sliced
• 1/2 cup celeriac (celery root), peeled and cut into very small cubes
• 1 cup butternut squash, peeled and cut into small cubes
• Handful of thyme sprigs, leaves only
• 1/2 cup sherry
• 1 cup chicken stock
• 1/2 cup crème fraîche (use sour cream if you HAVE to)
• One 6-ounce sheet frozen puff pastry, thawed
• Plain flour, for rolling
• 1 egg yolk, beaten with 1 tsp water
• 8 ounces cooked chicken, cut into chunks
• Sea salt and freshly ground black pepper

Steps

1. Cook the chicken. Use chicken thighs if you want to be sure the chicken does not dry out. I seasoned mine with salt and pepper and pan seared it with garlic and thyme sprigs. Set aside once done.
2. While the chicken is cooking, prep the vegetables.
3. Trim and slice the leek (cut off and discard the dark green. Slice in half longways down the stalk. Clean in between the layers, then slice along stalk)
4. Peel butternut squash and cut into small cubes.
5. Peel celeriac and cut into even smaller cubes (If you have them too big, the celery flavor will overpower your bites)
6. Fry the pancetta in a hot, dry pan for 3–4 minutes until lightly golden. Tip onto a plate lined with paper towels. Wipe out the pan.
7. Heat the oil in the pan and sauté the vegetables with the thyme and some seasoning for about 7 minutes until softened. Pour in the sherry and bubble for 5 minutes until well reduced. Return the pancetta to the pan and pour in the stock.
8. Return the liquid to the boil and cook for 10–15 minutes until reduced by half. Stir in the crème fraîche (sour cream if you absolutely cannot find crème fraîche) and cook for about 5 minutes until the sauce has reduced by about a third. Check for seasoning, then remove from the heat and set aside.
9. Preheat the oven to 400°. Roll out the pastry on a lightly floured surface to the thickness of about 1/4 inch. Cut out 2 or 3 rounds, using a small saucer as a template. Carefully place the pastry rounds on a large, non-stick baking sheet and score the surface in a diamond pattern, using the tip of a small sharp knife.
10. Brush the pastry with the egg yolk glaze and bake for about 10 minutes until risen and golden. Bake for a further 2 minutes with the oven door slightly ajar, to help crisp the pastry. Remove from the oven and slide onto a wire rack.
11. Meanwhile, add the chicken to the sauce and reheat until the meat is warmed through. Check the seasoning and divide the chicken mixture between your warmed serving plates. Top each pile with a pastry round and serve.