Heat oven to 160C/140C fan/gas 3. Grease and line a 2lb/900g loaf tin with a long strip of baking parchment. To make the loaf cake batter, beat the butter and sugar with an electric whisk until light and fluffy. Add the bananas in a few chunks and beat in with the eggs, flour, almonds, baking powder and milk until smooth - the whisk will mash the bananas. Stir in the pecans, then scrape into the tin. Bake for 45-50 mins until golden, risen and a skewer poked in comes out clean. Cool in the tin, then lift out.
Beat the butter, icing sugar and vanilla. Spread on top of the cooled cake and scatter with more chopped pecans