Unroll each sheet of all-butter puff pastry (2 pack) and roll it out a little thinner until you are left with a rectangular shape, 36cm x 26cm.
Cut each sheet into 3 equal strips, each 12cm wide, then stack them on top of each other to create 3 layers. Repeat with the second sheet of pastry.
Using an 11cm round cutter (or a small bowl), cut 2 circles from each layered pastry strip. You should have 4 circles in total. Place these on a lined baking tray.
Take an 8cm cutter (or a slightly smaller bowl) and gently press halfway into the centre of each pastry circle to form the shell. Pierce the inner circle with a fork a few times prevent it from rising too much. If the pastry has warmed up, pop it into the freezer for 5- 10 minutes to firm up.
Preheat the oven to 200°C/180°C fan/gas mark 6. Remove the pastry from the freezer and brush each one well with beaten large free-range egg (1). Sprinkle with a little salt and place the tray on the middle shelf of the oven and cook for 25 minutes, until risen and a deep golden brown.
Meanwhile, heat the light olive oil (2 tablespoon) and salted butter (30 gram) in a large nonstick sauté pan over a medium-high heat. When the butter is foaming, add the leek (300 gram) and cook for 2 minutes. Increase the heat, add the cauliflower (300 gram) and chicken stock (200 millilitre) and cook for a further 5 minutes. Add the lighter garlic and herb creamy soft cheese (250 gram), thyme leaves (2 teaspoon), and stir well until it has incorporated. Stir in the creamy Lancashire cheese (120 gram) and season to taste with salt and pepper.
Remove the vol-au-vents from the oven and leave to cool slightly. Using a spoon, press the middle part of the pastry down.
Spoon the warm filling into each pastry shell. Sprinkle with chive (as needed) to serve.
