Sprinkle gelatin over water in large bowl and let sit until softened, about 5 minutes.
Microwave mixture until bubbling around edges and gelatin dissolves, about 15 seconds.
Stir in butter, vanilla, and salt until combined.
Let mixture cool until just warm to touch, about 5 minutes.
Whisk in marshmallow crème until smooth; refrigerate marshmallow filling until firm enough to spread, about 30 minutes.
FOR THE FROSTING:
Bring 1/2 cup cream and cocoa to simmer in small saucepan over medium-high heat, whisking until smooth.
Pour cream mixture over white chocolate chips in small bowl and whisk until melted and smooth.
Let white chocolate mixture cool completely, about 30 minutes.
Using stand mixer fitted with whisk, whip remaining 1 cup cream with cooled white chocolate mixture on medium-high speed until soft peaks form, 60 to 90 seconds.
TO ASSEMBLE:
Place 1 cake layer on plate or pedestal. Spread half of filling in even layer over top.
Top with second cake layer and remaining filling.
Place third cake layer on top. Spread top and sides of cake with even layer of frosting.
Arrange marshmallows on top in large mound; dust with extra cocoa. Serve.
Homemade Reduced-Salt Chicken Stock Makes approximately 2.5–3 litres Ingredients * 1.5–2 kg chicken bones/carcasses * chicken frames are perfect and inexpensive * wings, necks and backs are also excellent * 2 large carrots, roughly chopped * 2 celery stalks, roughly chopped * 2 brown onions, quartered * 4 garlic cloves, lightly crushed * 2 bay leaves * 6–8 whole black peppercorns * Small handful fresh parsley, including stalks * 2–3 sprigs fresh thyme, optional * Approximately 3.5–4 L cold water, or enough to just cover everything * No added salt I actually recommend making it without salt altogether. Then when you use 1 cup in a recipe, you control the salt in that particular dish. It essentially becomes your own no-added-salt chicken stock. Method 1. Optional, but excellent for flavour: place the chicken bones on a roasting tray and roast at 200°C fan-forced for 30–40 minutes, until lightly golden. You don’t need them deeply browned. 2. Transfer the bones to a large stockpot. Add the carrot, celery, onion, garlic, bay leaves, peppercorns, parsley and thyme. 3. Pour over enough cold water to just cover everything. You don’t want excessive water because you’re aiming for a flavourful stock rather than a watery broth. 4. Slowly bring it just to a simmer. 5. Once simmering, turn the heat right down. You want the occasional gentle bubble — not a rolling boil. 6. Simmer uncovered for around 3–4 hours. Occasionally skim away any foam/fat that rises to the surface. Add a little hot water if necessary to keep the bones mostly submerged. 7. Strain everything through a fine sieve. Don’t press or mash the vegetables through; just allow the liquid to drain. 8. Return the strained stock to the clean saucepan and simmer uncovered for another 20–40 minutes, if needed, until you’ve got roughly 2.5–3 litres and the flavour is pleasantly concentrated. 9. Cool promptly, then refrigerate. Once completely cold, you’ll probably see a layer of chicken fat set on top. Lift this off for an especially low-fat stock.