To prepare a best ever vegan chocolate mug cake recipe, first you need to prepare the ingredients for the cake. First, you will need the following ingredients: 1 tbsp cocoa powder 12 cup granulated sugar 1 tablespoon vanilla extract Instructions: Preheat the oven to 375 degrees F. Line the bottom and sides of an 8 x 8-inch baking pan with parchment paper. Add the dry ingredients to the wet ingredients and stir to combine. Pour the batter into the prepared pan and bake for 20 to 25 minutes or until the toothpick inserted in the center comes out clean. Allow to cool before removing from the pan.