Mix other dry ingredients with the flour on a work surface or silicone pastry mat, then make a well in the center.
Add the vegan butter and eggs, then mix with your fingers or a pastry scraper until the dough becomes coarse crumbs.
Quickly knead the dough until it holds together. Shape it into a ball, then wrap with cling film, and chill for an hour.
Roll the chilled crust dough between two sheets of parchment paper.; aim for a thickness of 3-4 mm (1/4 inch) using dough measuring strips for equal thickness.
Prepare a 20 cm x 4 cm deep (8 in x 1.6 in) cake ring or springform cake pan. Carefully lift the dough to a tart ring or cake pan. Press the corners and edges. Check the bottom for any holes, then trim the edges. Chill for 10 minutes to rest the dough.
Fill the chilled shortcrust dough with pistachio-almond frangipane. Use a spoon or offset spatula to level the top.
Bake for 18 to 20 minutes in a preheated 185°C (365°F) oven. Place baked tart on a wire rack and cool at room temperature.