Chicken and Leek Pie - Ainsley Harriott

Ingredients

• 1 tbsp vegetable oil
• 25g butter
• 1 large leek, washed trimmed and cut into 1cm rings
• 1 onion, finely chopped
• 600g boneless chicken thighs, cut into 1.5cm cubes
• 2 sachets of Ainsley Harriott Chicken and Leek Cup Soup
• 1 heaped tbsp flour
• 300ml milk
• 125g frozen peas
• 1 pack ready rolled puff pastry
• 1 egg, beaten, to glaze