Cut vegan butter into cubes and pulse with flour and salt in a food processor until crumbly. Add cold water gradually until dough forms. Chill for 30 minutes.
Roll out 3/4 of the dough, fit it into a tart tin, and trim excess. Chill the tart and cut decorative shapes from the remaining dough.
Pre-bake the tart crust with parchment and baking beads at 350°F (175°C) for 15 minutes. Remove beads and bake 5 more minutes. Let cool.
Bake the shortcrust decorations brushed with plant milk and sugar for 10-15 minutes. Cool completely.
Blend silken tofu, coconut milk, sugar, spices, starches, and plant milk until smooth. Heat and whisk until thickened, then mix in spiced rum.
Pour custard into the tart crust, bake for 20 minutes until set around the edges but wobbly in the center. Cool fully.
Decorate with shortcrust shapes and serve.
