Make the filling: Soak the raisins in boiling water for 20 minutes to plump them up, then drain the water.
In a small bowl, cream the coconut sugar and vegan butter together until well combined, then mix in the soy milk, maple syrup, cornstarch, and vanilla. Stir in the plumped-up raisins and mix well.
Make the dough: In a large bowl, mix the 3 flours, cornstarch, and salt together. Cut in the cold vegan butter with a knife until it’s pretty finely chopped into crumbs (try not to use your hands too much or it will over-warm the dough). Then stir in the cold soy milk with a fork until you get a nice ball of dough coming together.
Split the dough into 6 equal pieces (you can use a scale if you want to be precise, or eyeball it). Press into six 4" tartlet tins, making sure the crust is not too thick on the bottom (or you can make 12 mini tarts in a muffin pan).
Spoon the filling into the pastry cups, all the way up to the top but not spilling over.
Bake at 325F for about 30 minutes (check after 20 minutes if using a muffin pan). They should be bubbling and a deep brown color when they’re done, with a golden crust.
Cool for 10 minutes, then remove from the tartlet tins and serve your Canadian butter tarts warm. They also freeze well for reheating at another tea time.