Preheat to 350°F (175°C) and grease two 9-inch round pans
Combine flour, cocoa powder, sugar, baking soda, and salt in a bowl.
Mix plant-based milk, oil, vinegar, and vanilla in another bowl.
Gradually mix dry ingredients into wet. Fold in chocolate chips if using.
Pour batter into pans and bake for 30-35 minutes. Check doneness with a toothpick.
Let cakes cool in pans for 10 minutes, then transfer to a wire rack.
Make frosting by mixing vegan butter, powdered sugar, cocoa, milk, and vanilla.
Frost between layers and cover the top and sides.
Add toppings like berries or chocolate chips. Serve and enjoy!