Preheat oven to 350°F (176 C). Line 24 muffin cups with paper liners.
Stir or whisk whatever non dairy milk you are using and vinegar together in a large mixing bowl. Let it sit for a few minutes to curdle.
Meanwhile, thoroughly mix together the flour, cocoa powder, baking soda, baking powder and salt; set aside.
Stir the sugar, oil and vanilla into the soy milk mixture and whisk until foamy.
Add half of the dry mixture (flour etc.) to wet mixture and stir very well until mixed – batter might be slightly lumpy, but try to remove the big lumps. Add remaining flour mixture and stir until mixed. Pour batter into muffin cups dividing evenly between all 24 cups and bake 20 minutes or until a toothpick inserted in center comes out clean.
To make the frosting, beat together the softened vegan butter and a little of the powdered sugar. Continue adding powdered sugar gradually, scraping bowl often. Add vegan milk and flavorings. Beat until light and fluffy. For the chocolate version, follow the same steps but add the cocoa powder with the confectioners sugar.