Preheat the oven to 180°C/ Gas 4. Make the pastry by crumbling the butter and flour, plus some salt & pepper together with your fingertips. Then add a little cold water, just a splash at a time, until the pastry comes together. Wrap in cling film and rest in the fridge for 15 minutes.
Dust a work surface with a sprinkling of flour and use a rolling pin to roll out the pastry to a thickness of about 5 mm. Use the cutter to cut out six 25 cm circles. Either leave the circles out if you've space or layer them with a little baking parchment in between to keep them separate.
To make the Cornish pasty filling, put the skirt steak, swede, carrot, onion, thyme and some salt and pepper in a bowl and mix well. Divide the Cornish pasty filling among each pastry circle and spread it out evenly on the right side of each circle, so that you can fold over the other side. Pull the left side over and press it together to seal 1 cm away from the edge of the right hand side of the pastry. This allows a little room to fold the edge back over the fold to seal in the filling nice and tightly.
Lay some baking parchment onto a baking tray (you can grease this a little with some butter, too, to be safe), slide a palette knife under the pasties and lift them carefully onto the paper. Bake in the preheated oven for 45 minutes, until golden brown. Serve while still warm - it makes for a hearty meal all on its own!
Cook's Tip: Make your pasties as authentic as possible by using local ingredients, like British beef and Cornish butter.