Chicken And Leek Pot Pie - cooking recipe

Ingredients

2 cups chicken stock
1 1/4 lb chicken breast fillets
1 tbsp olive oil
3 tbsp butter
1 lb leeks, thinly sliced
2 stalks celery, trimmed, finely chopped
2 tbsp flour
2 tsp fresh thyme leaves
1/2 cup milk
1 cup cream
2 tsp whole grain mustard
1 (8 inch) frozen pie shell, thawed
1 sheet frozen puff pastry, thawed
1 None large egg yolk

Preparation

Bring stock to a boil in a medium saucepan. Add chicken and return to a boil. Reduce heat and simmer, covered, for 10 mins, or until chicken is cooked through. Remove from heat and let stand in poaching liquid for 10 mins. Remove chicken and chop coarsely. Reserve 1/3 cup poaching liquid.
In a medium saucepan, heat oil and butter over medium heat. Cook leek and celery, stirring, until leek softens. Add flour and thyme. Cook, stirring, for 1 min. Gradually stir in reserved poaching liquid, milk and cream. Cook, stirring, until mixture boils and thickens. Stir in chicken and mustard. Let cool for 10 mins.
Preheat oven to 400\u00b0F. Prick base of pie shell all over with a fork and bake for 10 mins. Let cool for 5 mins then fill with chicken mixture. Place puff pastry over filling, trimming to fit dish. Brush with egg yolk then cut 2 small slits in the center. Bake for 20 mins, or until lightly browned.