Preheat oven to 350* F. Grease an 8x8 inch square baking pan and line it with a parchment sling for easy removal.
In a medium bowl, combine flour, baking powder, baking soda and salt. Whisk to combine and set aside.
1 ¾ Cup All-Purpose Flour, 2 teaspoon Baking Powder, ¼ teaspoon Baking Soda, ¼ teaspoon Kosher Salt
In a large bowl, combine sugar, non-dairy milk, melted vegan butter, lemon juice, and vanilla. Whisk well to combine. Then, add the dry ingredients and whisk to form the batter.
1 Cup Granulated Sugar, 1 Cup Non-Dairy Milk, 6 tablespoon Vegan Butter, melted, 2 teaspoon Lemon Juice, 2 teaspoon Vanilla Extract
Pour the batter into the prepared 8x8" square pan and bake in a 350*F oven for 35-40 minutes or until a toothpick inserted into the center of the cake comes out clean. Allow to cool completely before proceeding.