Preheat oven to 170C. Turn on ice cream machine to chill according to manufacturers instructions.
For the Lemon Aspen Sorbet, combine all ingredients in a small saucepan and stir over low heat until sugar has melted. Line a fine sieve with a double layer of muslin cloth. Strain mixture through the lined sieve into a clean bowl and chill over an ice bath. Transfer mixture to the ice cream machine and churn until set. Once set, transfer to the freezer until needed.
For the Roo Carpaccio, roll each kangaroo fillet tightly in cling film to form a log. Wrap tightly in a second sheet of cling film, secure ends to hold in a cylinder shape and place into the freezer for 30 mins to firm up. Remove from the freezer and unwrap. Slice ends off the fillets then cut into 20 thin slices.
Place each slice between two sheets of cling film and use a meat mallet to gently flatten into 1-2mm thick rounds. Season both slices of each piece with salt and pepper and set aside in the fridge until needed.
For the Smoked Quandong Mayo, place quandongs, grapeseed oil, white vinegar and salt into a stick blender canister. Carefully crack the egg into the canister, keeping the yolk intact.
Carefully insert the stick blender, making sure the blades completely cover the egg yolk. Blend, and as mayonnaise comes together, slowly bring blender up through the mayonnaise to incorporate all of the oil. Pulse the stick blender up and down until all the oil and quandongs are incorporated and mixture is emulsified.
Transfer mayonnaise to a medium bowl and seal with 2 layers of cling film. Insert the hose of a smoking gun and seal cling film again tightly. Light the smoking chips and allow the bowl to fill with smoke then remove the smoking gun hose and seal cling film again tightly. Allow to stand for 10 minutes.
Remove the cling film, fold in the fresh cheese and cream until fully combined then transfer to a piping bag and set aside in the fridge.
For the Wattleseed Crumb, place all ingredients into a food processor and process to a fine crumb.
Spread the crumb mixture onto a baking tray lined with baking paper and bake in the oven until golden, stirring occasionally to ensure even colouring, about 15 minutes. Remove from the oven and set aside to cool.
For the Crispy Sea Lettuce, pour enough grapeseed oil to fill a medium saucepan to a depth of 4cm. Place over medium heat and bring to 160C.
Tear each sea lettuce leaf into two pieces then very carefully drop sea lettuce leaves into the oil and cook for 10 seconds. Remove from the oil and drain on paper towel.
To serve, arrange 5 slices of the Roo Carpaccio in a circle in the middle of the plate, with each slice slightly overlapping. Pipe mounds of the Smoked Quandong Mayonnaise around the Roo Carpaccio. Break up some pieces of with Crispy Sea Lettuce and scatter over the Roo Carpaccio. Sprinkle the Wattleseed Crumb over the top. Spoon a rocher of Lemon Aspen Sorbet and place off centre on top of the Carpaccio.