How to "lighten" slightly bitter chocolate frosting?!
This is my favorite vegan chocolate frosting recipe:
Melt vegan semi-sweet chocolate (I use Enjoy Life mini chips) with oi. Stir in agave, vanilla, and a pinch of salt. Chill, and whip it all up with a hand mixer. SO GOOD!
To lighten up the flavor of the frosting you have already made, you can whip in some agave nectar or vegan powdered sugar (depending on if it could use thinning or thickening.) If it is a shortening based recipe, whip in a little more shortening.
If the frosting can't be altered itself, and you have already frosted your cakes, you can definitely top with some of the above mentioned Enjoy Life chocolate chips, or some chocolate or rainbow sprinkles from Let's Do...
You can also drizzle something over the finished cupcakes, like a strawberry or raspberry puree. Puree fresh or frozen berries with vegan sugar, and pass through a strainer to get the seeds out. I know you mentioned you don't have fresh strawberries, but maybe you have something you can use in the freezer?
Or, to go in a different direction, maybe you could make some kind of a nut or seed brittle and sprinkle shards of that on top.
If it is sweetened with agave, you can simply do a teeny drizzle of agave over each cupcake. If you used sugar, try adding a dusting of powdered sugar. (Try it on just one first, and wait half an hour to see how it looks before doing all of them. It may be absorbed completely or not at all, which would look fine - but it may be absorbed partially and look funny, so you should do a tester!)
Another drizzle idea is a syrup you make yourself. Over the weekend, I made an orange-almond syrup at work. Put orange juice in a non-reactive pot. Add a little sugar, and bring up just to a boil. Let it reduce until it's syrupy. Add some almond extract and some vanilla. If you and your audience are all of age, add a splash of rum or brandy too. Taste and see if it needs more sugar, more reducing, or more of something else. Cool completely, and then drizzle over whatever you want!
Good luck with your presentation!
You could add some banana? and make them banana chocolate muffins!! my favourite :) you can also buy dried banana bits, which you could put on top? xxx
raspberries are good too