Preheat the oven to 350°F & line a cupcake pan with paper liners
Combine the vinegar with the plant milk (soy milk is the only milk that will thicken with vinegar, but you can use another plant milk of your choice)
In a large mixing bowl combine the oil, brown sugar, salt, pumpkin & the thickened vinegar/plant milk along with the vanilla & whisk to combine well
Sift the flour with all the spices & the baking soda then add it all at once to the wet mixture in the bowl ~Whisk smooth
Portion batter into the cupcake liners filling 3/4 full & bake immediately in the preheated 350°F oven for 18-22 minutes or when they are springy to the touch when you gently press the centers
While they are cooling prepare the buttercream recipe by creaming the vegan butter with the optional salt on high speed to fluffy (about 3 minutes) scrape the bottom & sides of the bowl from time to time
Add the sifted confectioners sugar all at once & mix on low speed until incorporated then scrape the bottom and sides of the bowl again & mix on medium to high speed for another 3 minutes
Add the extracts last
If you are making some of the buttercream chocolate like I did, combine the cocoa paste & hot boiled water in a small bowl, whisk smooth then set aside & cool completely
Divide the buttercream in half into 2 separate bowls & add the cooled cocoa paste to one portion mixing it smooth to a silky chocolate buttercream
Pipe the vanilla buttercream onto the cooled cupcakes & then a swirl of chocoalte on top of that
I sacrificed one pumpkin cupcake to crumble up & sprinkle on the tops of each iced cupcake