Method

1. Place the chuck steak in a large bowl, sprinkle with the flour and toss to coat.
2. Heat 1 tablespoon of the oil in a large heavy-based saucepan over a high heat and cook half the steak chunks, stirring occasionally, for about 5 minutes or until sealed. Remove from the pan, scraping any cooked-on bits from the base, and set aside. Repeat with another tablespoon oil and the remaining steak.
3. Clean the pan if necessary. Add the remaining 1 tablespoon oil, onion and shiitake mushrooms and cook over a medium-high heat, stirring occasionally, for 5 minutes or until the onion and mushrooms start to soften. Reduce the heat to medium, add the garlic and ginger and cook for a further 1 minute, stirring occasionally, or until aromatic. Return the steak to the pan with the stock, water and 1 tablespoon of the oyster sauce and bring to a simmer.
4. Reduce heat to low and simmer, covered, for 30 minutes, stirring occasionally. Uncover and then simmer for a further 30 minutes to 1 hour, stirring frequently or until the meat is tender and the liquid has reduced and thickened to a thick sauce consistency. Stir in the remaining oyster sauce, taste and adjust seasoning by adding a little more oyster sauce if necessary. Transfer the mixture to a heatproof bowl, cover and place in the fridge, stirring occasionally, until cooled to room temperature (this will take about 2 hours).
5. When ready to assemble the pies, preheat oven to 220°C (200°C fan-forced). Brush 6 x 10.5cm (base measurement) x 14cm (top measurement) metal or foil pie dishes. Unwrap the pastry discs and divide each into quarters. Shape a quarter into a disc and use a lightly floured rolling pin to roll the pastry on a lightly floured bench top into a round until about 3mm thick and about 15cm in diameter. Repeat with the remaining discs. Use an upturned pie dish to cut out pie lids from 6 of the rolled pastry rounds. Use the end of a 1cm piping nozzle or a small sharp knife to cut a small steam hole in the centre of each pie lid.
6. Gently ease the the uncut pastry discs into the pie dishes and use your fingertips to press the pastry gently into the corners without stretching it — it will overhang the dishes slightly. Divide the steak mixture between the pastry cases to fill. Place a lid over the mixture to cover each pie, brush the edge of each lid with the whisked egg and then fold the excess pastry from the bases over the top of the lids, crimping with your fingertips or pressing with a fork together to seal. Brush the top of each pie lightly with some of the remaining egg wash and sprinkle with sesame seeds.
7. Reduce the oven to 200°C (180°C fan-forced) and bake the pies in preheated oven for 45-50 minutes or until the pastry is cooked through and a deep golden. Stand the pies in the dishes for 5 minutes before turning out and serving.