1. Prep: Preheat the oven to 350 F. Grease three 6″ cake pans or 8″ cake pans with cooking oil, and line them with parchment paper. Set aside.
2. Prepare the vegan buttermilk: Combine the dairy free milk with the apple cider vinegar, and set aside to sit for 5-6 minutes. You can weigh and measure the remaining ingredients during this time. 
3. Whisk the dry ingredients: In a medium bowl, whisk together the flour, baking powder, and baking soda. Set aside.
4. Make the batter: For beginner bakers who want to simply whisking the ingredients together, see below for instructions. In a stand mixer with paddle attachment or a large bowl with hand mixer, cream together the vegan butter and sugar until fluffy, about 2-3 minutes. Scrape down the sides as needed. Then add in the applesauce and vanilla extract. Mix again on medium speed until combined, scraping down the sides and at the bottom of the bowl as needed. Add in about half of the dry mixture, along with half of the vegan buttermilk, and mix on medium speed until just combined. Add in the remaining dry mixture and vegan buttermilk, and mix on medium speed until there are just no more dry streaks. Make sure to scrape the bottom of the bowl as well as the sides.
5. Bake: Divide the batter between the three cake pans evenly, and bake for 35 minutes in 6″ cake pans, or until the toothpick comes out clean. (for three 8″ cake pans, bake for 27-30)
6. Cool: Remove from the oven and allow the cakes to cool in their pans for 10 minutes, then transfer them to a cooling rack to cool completely. Once cooled completely (there is absolutely no warmth to the touch!), then you can prepare your buttercream.

Vegan Vanilla Buttercream:

1. When ready to frost the cakes, add vegan butter to a large bowl or stand mixer and cream for 2-3 minutes.
2. Add in 1 cup of powdered sugar at a time, continuing the beat the mixture until it’s a thick buttercream.
3. Add in vanilla and 2-4 tablespoons of coconut/almond milk and continue to beat until desired texture.
4. Frost cake and enjoy!