400 g (13 oz) ready-prepared vegetable casserole mix (carrots, swede, turnip and potato cubes), roughly chopped into about 1 cm (1/2 inch) cubes if too large
125 g (4 oz) mature Cheddar cheese, grated
1 tablespoon dried thyme
beaten egg, to glaze
Roll out the pastry on a lightly floured surface and cut out 4 x 25 cm (10 inch) circles, using a plate if necessary.
Put the melted butter and oil in a bowl with the vegetables and toss well. Season with plenty of pepper and toss again. Add the cheese and thyme and toss well. Divide the vegetable and cheese mixture between the 4 circles of pastry. Dampen the rims of the pastry using a brush and a little water, then lift the pastry edges up and over the filling to meet one another and pinch together to hold in a pasty shape. Place on a large baking sheet and crimp the edges using your fingers.
Brush with beaten egg and bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 20 minutes until golden and cooked through. The vegetables cook in their own steam inside the pastry and should be tender.