Preheat your oven to 375 degrees, and line medium cupcake tins with papers.
Mix all the dry ingredients in a medium size bowl.
Combine all the wet ingredients in separate bowl, except for the vinegar.
Slowly add your wet ingredients to the bowl of dry ingredients and stir until everything is combined, but do not overmix - a few lumps are okay.
Add the vinegar and quickly stir in.
Pour batter into the pans and immediately and put them in the oven. Bake for about 15 -20 minutes.
Take cupcakes out of the oven and put one marshmallow on top of each cupcake and put the pan back in the oven for more or less one minute just to soften the marshmallows.
Take the pan out of the oven and lightly press two fingers on top of the mallows to flatten it, be careful because it's melted inside and really hot!
Top each cupcake with a few pieces of chocolate chips for garnish, if you want. Enjoy!