Preheat oven to 350°F/175°C. Spray two round cake pans with vegetable spray. You can also place a piece of parchment paper at the bottom of the pans and spray the sides with vegetable oil.
Combine in a large mixing bowl the flour, sugar, cocoa, salt baking soda, and cornstarch. Stir to combine.
In a smaller bowl, combine the vegetable oil, water, vinegar, vanilla, and food coloring. Stir to combine.
Pour the water mixture into the flour mixture and gently fold until just combined. Do not overmix.
Pour the batter into prepared cake pans. Bake for 30–35 minutes until a toothpick inserted in the middle comes out clean.
Allow the cakes to cool for about 10 minutes before inverting onto a plate. Allow cooling completely before frosting.
Vegan Cream Cheese Frosting
Cream together the vegan butter and vegetable shortening in a mixing bowl using either a handheld mixer or a stand mixer with the paddle attachment. Cream for 1–2 minutes until light and fluffy. Add the vinegar and lemon juice and mix again for another minute.
In a bowl combine the powdered sugar and salt. Whisk to combine. Add this to the butter mixture and mix on low until mostly combined, scraping down the sides of the bowl as needed. Add the vegan creamer, one tablespoon at a time, mixing in between each addition. Continue until you get a smooth, spreadable consistency.
Once the cakes cool, use a serrated knife to slice a thin layer off the tops of the cakes to create a level surface. Reserve shaved cake shreds. Place one cake on a serving plate or cake stand. Top with a third of the frosting. Place the second cake on top and frost the top and sides of the cake. You'll need every last bit of the frosting, so be sure to use a spatula to get it all.
Place shaved cake bits in a food processor and pulse until crumbly. Decorate the cake with red velvet cake crumbles.
Allow the cake to set for about 30 minutes before serving. Use a cake keeper to cover the cake. It will keep at room temperature for up to 3–4 days, or in the fridge for up to 7 days. You can cut it into individual slices and freeze the slices. They will keep if properly stored for up to 2 months.
Make-Ahead Tips: After layers are baked, cool them completely, and cover in an airtight container. They can be stored overnight at room temperature. You can also prepare the frosting the day before. Simply store in the fridge in an airtight container. Be sure to let it sit at room temperature for about 15 to 20 minutes before frosting the cake.
Food Coloring: For this vibrant red cake, I used 2 tablespoons of red food coloring. If you have gel, use 2 to 3 teaspoons. However, you don't have to use any food coloring at all (the cake won't be red, but will still taste great) or see post tips for natural options.
Sheet Cake: If you prefer a sheet cake over a layered cake, pour batter into a 9x13" cake pan or 12x17" sheet pan. Bake at the same oven temperature for 40–45 minutes for the 9x13" pan or 20 to 25 minutes for the 12x17" pan. Use a tester to test for doneness.
Nutrition estimate includes both the cake and the frosting.