Preheat the oven to 350 F. Line a 12 cup cupcake pan with paper liners.
In a small bowl, combine the ground flax meal with 6 tablespoons of water and set aside to thicken.
In a large bowl, whisk together the flour, sucanat, baking powder, baking soda, ginger, cinnamon, sea salt, and nutmeg.
In a large bowl, combine the flax meal mixture with the sweet potato, coconut oil and vanilla and mix well. Add to the dry ingredients mixture and combine with an electric hand mixer on medium speed until smooth.
Divide the batter among the cupcake liners, filling them almost to the top. Bake for 22 to 25 minutes, or until a toothpick inserted into the centre of a cupcake comes out clean.
Let the cupcakes cool completely on a wire rack before frosting with vanilla buttercream and top with marshmallows.