Preheat your oven to 350°F (175°C).
Grease two 9-inch round cake pans with oil and line the bottoms with parchment paper.
In a large mixing bowl, whisk together the flour, cocoa powder, baking soda, and salt.
In another bowl, mix together the sugar, applesauce, oil, vanilla extract, and water until smooth. Add the food coloring and vinegar, stirring until fully incorporated.
Gradually add the wet mixture to the dry ingredients, stirring gently with a spatula until just combined.
Divide the batter evenly between the prepared cake pans and smooth the tops.
Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Let the cakes cool in the pans for about 10 minutes, then transfer to a cooling rack to cool completely.
Once cooled, frost with your favorite vegan frosting and serve.