Preheat the oven to 200˚C/400˚F/Gas Mark 6. Line a muffin tin with 12 cases.
For the banana and cinnamon muffins: in a large mixing bowl, mix the eggs, milk and sugar until pale and fluffy then add in the melted butter and mix until fully incorporated.
Stir in the mashed bananas and add the vanilla extract and stir.
In a separate, clean bowl sift together the flour, baking powder and cinnamon.
Mix the wet ingredients into the dry ingredients folding gently.
Spoon the mixture into the cases until 3/4 full.
Bake in the middle of the preheated oven for 15-20 mins.
Remove the muffins from the oven when cooked or when a skewer comes out clean after being inserted into the middle and leave to cool completely on a wire rack before decorating.
For the cream cheese frosting: beat together the icing sugar and butter. Add in the full-fat cream cheese and a generous sprinkling of cinnamon to taste.
Beat well until smooth. Decorate each cake with a dollop of the frosting (less is more as the cakes themselves are quite sweet already) and sprinkle with cinnamon to finish.