Preheat oven to 180°C fan bake. Slice the sheet of pastry into 4 pieces, brush with milk, sprinkle with sesame seeds and bake until golden and crispy.
While the pastry is cooking, heat a large frying pan and sauté the leek in a little oil until softened.
Add the crushed garlic and cook for 2 minutes. Stir through the corn and shredded chicken.
Pour in the cream and chicken stock, then simmer gently.
Mix the cornflour with water to make a slurry, then pour it into the pan. Bring to a boil and cook until the mixture thickens. Season to taste.
Spoon the creamy filling onto plates and top with a piece of the crispy pastry to serve.
