Preheat your oven to 350°F (175°C).
Grease an 8x8-inch baking dish.
In a large bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt.
In another bowl, mix the cooled coffee, dairy-free milk, vegetable oil, vanilla extract, and apple cider vinegar until smooth.
Add the wet ingredients to the dry ingredients, mixing until just combined.
Pour the batter into the prepared baking dish and spread it evenly.