Vegan Vanilla Cake with Buttercream Frosting

Name: Vegan Vanilla Cake with Buttercream Frosting
Prep time: 30 min
Cook time: 40 min
Total time: 1 h 10 min
Cuisine: American
Ingredients: 2 tablespoons apple cider vinegar; 2 cups soy milk (or other vegan milk (480mL), room temperature); 2 cups brown sugar (or cane sugar (400g)); 3 cups all-purpose flour ((360g)); 2 teaspoons baking soda ((10g)); 1 teaspoon sea salt ((2.8g)); ⅔ cup vegan butter (melted and cooled (150g)); 1 tablespoon vanilla extract; 3-3 1/2 cups powdered sugar; 1 cup vegan butter (softened); 1 teaspoons vanilla extract; 1 tablespoons vegan milk (add more if needed); 1/4 teaspoons sea salt (only if using unsalted butter)