1.Bring stock to the boil in a medium saucepan over high heat. Add chicken; return to the boil. Reduce heat, simmer, covered, for 10 minutes or until chicken is cooked. Remove from heat; stand chicken in poaching liquid for 10 minutes. Remove chicken; chop coarsely. Reserve 1 cup of the poaching liquid; keep remaining liquid for another use, or discard.
2.Heat butter in a medium saucepan over medium heat; cook leek and corn, stirring for 5 minutes or until softened. Add paprika, cook, stirring, for 1 minute. Combine reserved poaching liquid and cornflour in a jug. Stir into leek mixture, with milk and cream. Cook, stirring, until mixture boils and thickens. Stir in chopped chicken and kale. Season to taste. Cool for 15 minutes.
3.Meanwhile, preheat oven to 200°C. Grease a 22cm x 30cm oval 2-litre (8-cup) ovenproof dish.
4.Roll the pastry between two sheets of baking paper to make a 5mm (¼in) thick, 35cm x 40cm (14in x 16in) rectangle. Cut pastry crossways into 5cm (2in) wide strips.
5.Spoon chicken mixture into ovenproof dish; place pastry strips crossways, slightly overlapping each other, over pie filling. Press edges to side of dish; trim excess. Brush pastry with egg yolk mixture; sprinkle with sesame seeds. Make a small cut in the centre of the pastry.
6.Bake pie for 35 minutes or until golden brown and filling is heated through.
Gluten-free shortcrust pastry
7.Place pastry mix in a large bowl; rub in butter with your fingers until mixture resembles coarse breadcrumbs. Combine ²⁄³ cup (160ml) water, tamari and oil in a jug. Using a flat-bladed knife, ‘cut’ wet ingredients through dry ingredients until mixture forms a dough. Lightly knead dough on a surface dusted with a little gluten-free flour into a ball.
8.Roll pastry between two sheets of baking paper until 5mm (¼in) thick. Use this pastry for any of your favourite savoury recipes that use a shortcrust pastry.
Pie is best eaten on the day it is made.
Pastry is best used immediately. Rolling the pastry between sheets of baking paper will prevent the dough from sticking to the bench. If pastry dries out while you are using it, add a little more olive oil to the dough. If pastry cracks when you are rolling it out or placing it into tart cases etc., it can quickly and easily be pushed back together without ruining it.