Mix in milk, eggs and margarine until smooth. In a separate bowl, combine flour, sugar, baking powder, salt, cinnamon and nutmeg. Stir dry ingredients into banana mixture.
Heat oil in a deep fryer or heavy bottomed pan to 375 degrees F (190 degrees C). Drop batter by spoonfuls into hot oil, and cook, turning once, until browned, 2 to 8 minutes.
Drain on paper towels and dust with confectioners' sugar.