Preheat the oven to 100C/210F/gas mark 1/4 and line two baking sheets with baking parchment.
Pipe bone shapes on one of the baking trays – start by piping a blob then work your way down to make the length, then finish with another blob on the opposite side. Repeat in reverse to make a crisscross, overlapping your meringue down the length of the bone to ensure there are no thin spots. It may take a few attempts to get the technique right.
Pipe ghosts on the other tray - start with a fat blob and tail off towards the top. Use a toothpick with a blob of meringue on the end to form arms.
Bake for about 1 hour until firm and the meringues lift away from the parchment cleanly. Remove from the oven and allow to cool.
Once cool, use a fine, food-only paintbrush to paint faces on the ghosts then store in an airtight container.
Turn the oven up to 150C/325F/gas mark 3. Line a baking sheet with baking parchment.
Sift over the cornflour and drizzle over the vanilla extract; fold through carefully until well combined.
Dollop about 2/3rds of the meringue onto the baking sheet and spread it out into an approx 20cm/8in circle. Use the rest of the meringue to build up the sides so that it is sort of bowl shaped.
Place the meringue in the oven and immediately turn the heat down to 100C/210F/gas mark 1/4. Bake for 1 hour 20 minutes then turn off the oven and leave the pavlova in there until it has cooled completely (to help prevent it from cracking). Once cool, store in an airtight container.
Place all the mixed berry coulis ingredients into a medium sized heavy bottomed saucepan and bring to the boil over a gentle heat, stirring regularly. Reduce to a simmer and cook for about 15 minutes, or until thickened. Allow to cool, then transfer the coulis to a blender or use a hand blender to purée until completely smooth, pass the puree through a sieve, pushing through as much pulp as possible and discarding any seeds. Transfer to a jug, cover and keep refrigerated.
When you are ready to serve the pavlova, carefully transfer it to a serving platter. Place the Oreos in a food processor and blitz until finely ground (or place in a freezer bag and bash with a rolling pin).
Whisk the cream with the icing sugar and vanilla bean paste until soft peaks form. Top the middle of the pavlova with the whipped cream.
Drizzle over some of the coulis, letting it drip down the sides gorily; if it is too thick then you can thin it with a little water. Serve the rest on the side in a jug for people to pour over.
Scatter over the crushed Oreos then top with a pile of meringue bones and your favourite ghosts. Serve straight away and keep any leftovers refrigerated.