Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans or line them with parchment paper.

In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, baking soda, and salt.

In a separate bowl, whisk together the unsweetened almond milk, vegetable oil, apple cider vinegar, and vanilla extract.

Pour the wet ingredients into the dry ingredients and whisk until the batter is smooth and well combined. Be careful not to overmix.

Divide the batter equally between the prepared cake pans and smooth the tops with a spatula.

Bake in the preheated oven for approximately 25-30 minutes, or until a toothpick inserted into the center of the cakes comes out clean.

Remove the cakes from the oven and let them cool in the pans for about 10 minutes. Then, transfer the cakes to a wire rack to cool completely.

While the cakes are cooling, prepare the frosting. In a mixing bowl, beat the vegan butter until creamy. Gradually add the powdered sugar, almond milk, and vanilla extract. Beat until the frosting is smooth and fluffy.

Once the cakes have cooled completely, place one cake layer on a serving plate. Spread a layer of frosting on top. Place the second cake layer on top and frost the top and sides of the cake with the remaining frosting.

Decorate the cake as desired with additional toppings, such as fresh fruit, edible flowers, or sprinkles.

Slice and serve the vegan vanilla cake, and enjoy!