Mix the oil and sugar.
Add in eggs & vanilla. Whisk until blended.
Mix the dry ingredients in a separate bowl and whisk them into the liquid mixture.
Fill the cupcake liners halfway with the batter.
Place one marshmallow in the center of each liner.
Bake for 20 minutes. When they come out of the oven they might look a little sad, but that we fix that with our next step.
Place another marshmallow in the crater that was created by the first marshmallow.
Bake for another 2 minutes.
Frost and enjoy!