firstly, in a large bowl take 1 cup buttermilk, 1 cup sugar, ½ cup oil and 1 tsp vanilla extract.
mix well with the help of whisk for 5 minute.
further sieve 1¼ cup maida, ¼ cup cocoa powder, 1 tsp baking powder and ¼ tsp baking soda.
mix well using cut and fold method.
scoop the cake batter and pour into cupcake liners two-third to ¾ full.
preheat and bake the cake at 180 degree celsius or 356 degree fahrenheit for 30 minutes.
finally, decorate the chocolate cupcake with chocolate buttercream frosting and serve.