Heat oven to 160ºC/140ºC fan/gas 3/320ºF Line a 2lb/900g loaf tin with baking paper.
Cream the butter and sugar until light and fluffy, beat in the eggs followed by the flour, baking powder, cocoa powder and malt powder. Slowly add the milk and beat until the batter has loosened and all the ingredients are fully combined.
Transfer the cake batter to the loaf tin and bake in the centre of the oven for 45 minutes or until a skewer inserted into the centre of the cake comes out clean. Leave the cake to cool completely in the tin while you make the Malteser buttercream.
To make the Malteser Buttercream
Beat the softened butter until pale and creamy.
Add the icing sugar to the butter and beat for 3-4 minutes.
Add the Maltesers spread, vanilla extract and double cream and continue to beat until smooth.
Transfer to a piping bag fitted with a large open star nozzle (see notes) and pipe the buttercrean on top of the cooled chocolate and malt loaf cake.
Decorate with whole and crushed Maltesers.
Video
Notes
To make the cake batter you can use an electric handheld whisk, stand mixer with the paddle attachment or mix by hand.
You can snip the end off a piping bag and use it without a nozzle or spread the buttercream on top of the cake using a palette knife
Malteser Loaf Cake will keep fresh in an airtight container for up to 5 days.