Preheat your oven to 350 degrees F (175 degrees C) and lightly grease an 8-inch round cake pan, lining the bottom with a circle of parchment paper.

In a small bowl, whisk together the almond milk and apple cider vinegar, letting it sit for 5 minutes to curdle into a quick vegan buttermilk.

In a large mixing bowl, sift together the all-purpose flour, granulated sugar, cocoa powder, baking soda, and salt until evenly combined.

Pour the vegan buttermilk, unsweetened applesauce, vegetable oil, and vanilla extract directly into the dry ingredients.

Whisk everything together until the batter is smooth and no large lumps remain, being careful not to overmix.

Pour the batter into the prepared cake pan and tap it gently on the kitchen counter a few times to release any trapped air bubbles.

Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean and the edges begin pulling away slightly from the pan.

Let the cake cool in the pan for 10 minutes before turning it out onto a wire rack to cool completely, then serve with fresh berries or a dusting of powdered sugar.