Preheat the oven and prepare mini cake pans.

In a bowl, combine soy milk and vinegar; let it sit for a few minutes to curdle.

Add aquafaba, vegan butter, and vanilla extract to the soy milk mixture and mix well.

In a separate bowl, combine cake flour, baking powder, salt, and sugar.

Gradually mix the dry ingredients into the wet ingredients until well combined.

Pour the batter into the prepared mini cake pans.

Bake for 35 minutes or until a toothpick comes out clean.

Allow cakes to cool completely before frosting.

For the vegan buttercream, combine powdered sugar, dairy-free milk, and vanilla extract with food coloring until the desired color is achieved.

Frost the cooled cakes with the vegan buttercream.