Line a cupcake, try with liners and set aside. Preheat your oven to 350°F (180°C).
Sieve flour and cocoa powder in a mixing bowl and combine white sugar, brown sugar, baking soda, and salt with it.
Evenly distribute the batter on your cupcake tray with liners.
Evenly distribute the batter on your cupcake tray with liners.
Put the tray in the oven and bake for 20 minutes. Check by inserting a toothpick into the center of the cupcake; if it comes out clean, they are ready.
Let the cupcakes cool for a few minutes at room temperature, remove them from the tray, and then place them on a wire cooling rack.
Take vegan butter, powdered sugar, cocoa powder, vanilla, and salt in a mixing bowl. Use a hand mixer and start slowly and gradually increase the speed. Slowly add soy milk into this (only as much as you need) to get the right consistency.
After they have cooled down properly, pipe on the vegan chocolate buttercream frosting and sprinkle some grated vegan chocolate.