24 vegan ladyfingers, 125 g pistachio butter, 700 g vegan mascarpone
Make the sabayon: Add the soy milk, sugar, and cornstarch to a heavy-bottomed saucepan and whisk well until smooth without any visible lumps. Bring to a simmer over medium-high heat while whisking. Turn the heat down to medium and continue to cook for 6-8 minutes, while constantly stirring with a spatula or whisk, until you have a thick custard. Remove from the heat and allow to cool for 15 minutes before transferring to the fridge to chill completely for 1 hour.
400 ml soy milk, 120 g granulated sugar, 45 g cornstarch
Pistachio topping: Add the pistachios and sugar to a food processor and blitz until finely ground, and set aside.
30 g raw shelled pistachios, 15 g granulated sugar
Make the filling: Add the sabayon to a large mixing bowl and whisk for 1-2 minutes until smooth. Slowly add the vegan mascarpone in 3-4 increments, whisking between each one to incorporate it into the mixture.Lastly, add the pistachio butter in 2-3 increments, whisking between each one.Transfer it to one large or two small piping bags and secure the tops with an elastic band - (you can skip the piping bags and just use a spoon later if preferred).
Make the Amaretto-soak: Add the water and sugar to a saucepan and bring to a simmer. Whisk until the sugar is dissolved and remove from the heat. Whisk in the Amaretto.
60 ml Amaretto, 80 ml water, 50 g granulated sugar
Assembly: Quickly and individually dip half of the ladyfingers in the Amaretto syrup, immediately arranging each one on the base of the baking dish.Pipe half of the pistachio mascarpone in an even layer on top of the ladyfingers, then use an offset spatula to smooth out the top. You can simply spoon the mixture instead of using a piping bag if you like.Repeat this process with the remaining ladyfingers but this time pipe peaks on top with the remaining pistachio mascarpone.Sprinkle the pistachio sugar on top of the tiramisu.
Set in the fridge: Carefully and loosely cover the baking dish with some plastic wrap and refrigerate the tiramisu for at least 2 hours, or up to 24 hours.
Storage: Place in an airtight container and refrigerate. The quality is best if eaten in the first two days.
Notes
Granulated Sugar: Use organic if based in the US to ensure it's vegan-friendly.