Preheat your oven to 350°F (175°C).
Grease and line an 8-inch round cake pan or a 9x9-inch square pan with parchment paper.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In another bowl, mix the applesauce, plant-based milk, melted coconut oil, lemon juice, lemon zest, vanilla extract, and apple cider vinegar.
Add the wet ingredients to the dry ingredients, stirring until just combined. Do not overmix.
Pour the batter into the prepared pan and spread it evenly.