To make the poached pear, peel pear, reserving skin. Cut in half vertically and scoop out the core and stem. Put the halves into a vacuum bag with buttermilk, vacuum and seal.
Bring a saucepan of water to a simmer, add pear and cook for one hour. Remove from simmering water and chill.
Slice pear skins into fine long matchsticks. Place skins on a baking tray and place in the oven to dry for 1 hour. Remove from oven and set aside.
To roast the white chocolate for the ganache, place white choc in a metal bowl and place in the oven to caramelize, about 30 minutes, stirring during this time to ensure it caramelizes evenly. Remove from oven, transfer into a tall jug and set aside.
Make oxidized pear juice, for the sorbet. Peel pears and remove cores, roughly chop and place in a blender. Process until smooth, adding a little water to get it moving properly, cover and leave until brown and oxidized, about 40 minutes.
To make the ganache, place milk and 10 grams cream in a saucepan and set over medium heat. Bring to a boil, add gelatine and pour over caramelized white chocolate, blend with a stick blender until emulsified with no lumps. Add remaining 40 grams cream and blend well. Transfer mix to a piping bag with a small nozzle tip. Set aside to chill in an ice bath.
To make the sorbet, place glucose sugar and a small amount of oxidized juice in a saucepan and set over medium heat. Heat until dissolved then transfer to a blender. Add the remaining pear juice, and fresh pear and blend to combine. Cool over an ice bath and churn in an ice cream machine.
To make the toasted walnuts, increase oven temperature to 200C. Place the walnuts and vegetable oil in a small bowl. Sprinkle with the salt and sugar and toss to coat evenly. Transfer to a baking tray and place in the oven. Bake until light golden. Remove from oven, cool, chop roughly and set aside.
To make the walnut praline, place walnuts in a single layer on a paper lined tray. Place in the oven to lightly toast. Meanwhile, place sugar and 40 grams water in a saucepan and set over medium heat. Cook to a golden caramel, pour over walnuts and cool, chop and set aside.
To make the walnut powder, place the walnuts on a baking tray and place in the oven to lightly toast. Remove from oven and transfer to a food processor. While still warm, add the oil and a small pinch of salt, blend until smooth. Add the maltodextrin and pulse until a powder forms. Set aside.
To make the salted caramel, place butter in a small pot and cook until browned, add the cream to stop it cooking. In another small pot cook the sugar and 20 grams water to a deep golden caramel, take off the heat and very carefully add the cream butter mix, whisk together and bring to the boil, remove from heat, season to taste with sea salt, pour into containers and set aside in an ice bath.
Make the walnut crumb by mixing the toasted walnuts, walnut praline, walnut powder and muscovado sugar together.
To assemble, drain buttermilk from pears and rinse pears under cold water. From each half take two slices to get two pear cross sections from each half. Place poached pear onto the plate, add 3 small pieces of salted caramel, place pear batons on top, add the walnut crumb, pipe the ganache around, add a scoop of sorbet and finish with the dried pear skins.