Best Vegan Banana Cake - Nora Cooks

Name: Best Vegan Banana Cake - Nora Cooks
Cuisine: American
Ingredients: 3 large ripe bananas (1 1/2 cups mashed); 2 cups unsweetened soy milk; 2 teaspoons apple cider vinegar; 3 tablespoons ground flaxseeds; 3 cups all purpose flour; 2 teaspoons baking powder; 1 teaspoon baking soda; 1/2 teaspoon ground cinnamon; 1/2 teaspoon salt; 3/4 cup vegan butter, softened; 1 cup granulated sugar; 1/2 cup brown sugar, packed; 2 teaspoons pure vanilla extract; 8 ounces vegan cream cheese; 1/2 cup vegan butter, softened; 3 cups powdered sugar; 1 teaspoon pure vanilla extract; chopped walnuts, optional for topping