Heat oven to 350 and butter a 8×8 or 9×9 pan, set aside.
In a medium bowl beat butter and sugar until fluffy. Add the mashed banana and beat until smooth. Add the yogurt, vanilla, and egg and beat until well blended.
In a small bowl whisk flour, baking powder, salt, baking soda, and nutmeg. Stir the dry ingredient into the wet until thoroughly blended and no traces of flour remain.
Spoon the batter into the buttered pan and bake 25-35 minutes or until a toothpick inserted in the middle and removed comes out dry, or the cake springs back when lightly touched.
Let cake cool completely before frosting.
To make the frosting combine the cream cheese, butter, honey, and vanilla in a medium bowl and whip on high until light and fluffy. Add the powdered sugar and beat until smooth. Spoon the frosting onto the cooled cake and smooth with a spatula and serve.
This cake will last several days covered in the fridge, or for a several months wrapped well and frozen, that is assuming you didn’t eat it in one sitting.
Serves 9-12 depending on how big a piece you like.