Start with the vanilla custard: In a saucepan, combine the almond milk, coconut cream, and maple syrup. Add the potato starch and cornstarch and whisk until dissolved.
Heat over medium heat, whisking constantly until it starts to thicken. Once the milk has thickened, remove from the heat and stir in the vanilla extract. Divide the vanilla custard into 3 small jars.
Let cool a few minutes before transferring to the refrigerator. Refrigerate for at least 30 minutes.
Next, prepare the salted caramel layer: in a small bowl, combine the almond butter, coconut oil, maple syrup, vanilla extract, and salt. Taste and adjust saltiness to your liking. Divide the salted caramel into the three jars, on top of the vanilla custard. Refrigerate for another 30 minutes, or until the salted caramel is slightly firmer.
Finally, prepare the chocolate mousse: Melt the chocolate chips over a double boiler. Remove from heat as soon as the chocolate is melted. At this point, you can stir in the hazelnut butter if using. Set aside.
Pour the aquafaba into a large mixing bowl and whip it using an electric hand (or stand) mixer until it forms stiff peaks. This step can take up to 5 minutes.
Next, pour the melted chocolate over the whipped aquafaba and carefully mix using a spatula until combined. Try not to overmix, stop as soon as it’s combined and no white parts remain.
Divide the chocolate mousse into the three jars, on top of the salted caramel and top with crushed nuts or chocolate chips. Refrigerate for at least 1 hour, or until the chocolate mousse is set. Serve chilled.
These parfaits will keep for up to 3 days in the refrigerator.