Pre heat oven to 180°C degrees and line a 12 cup muffin tin with patty pans.
With a whisk, beat together the melted butter, sugar, salt, vanilla and eggs. Add the milk and whisk until smooth.
In another bowl, sift the coconut flour and baking powder twice. Add these dry ingredients to the wet ingredients and stir to combine. The cupcake batter will appear thinner than normal to achieve a light and fluffier texture.
Divide the batter between each of the patty pans and bake on the centre rack of the oven for approx. 20 minutes until the tops are golden and spring back when lightly touched.
Allow the cupcakes to cool for 5 minutes in the pan before transferring them to a rack to cool completely.
To make the frosting, beat the butter with an electric mixer until pale and fluffy. Add the vanilla, sugar and milk and beat until smooth. Add a little more sugar or a little more milk a drop at a time to adjust the consistency. Lightly tint buttercream with 1-2 drops pink food colouring (if desired).
Pipe buttercream swirls on each cupcake and then decorate with marshmallows bunny ears. To make the ears, combine sugar and food dye in a small bowl and mix until the sugar is tinted pink. Cut the marshmallows in half and dip the cut side into the sugar. Arrange the marshmallows on top like bunny rabbit ears.