Ingredients

  • 75 g walnuts, roughly chopped
  • 175 g butter
  • 150 g caster sugar
  • 275 g plain flour
  • 1 tsp vanilla essence
  • 3 medium eggs
  • 1/2 tsp baking powder
  • 2 tbsp cocoa powder
  • 75 ml buttermilk
  • 2 medium bananas, peeled and sliced
  • 2 tsp lemon juice
  • 25 g milk chocolate

Method

  • Preheat oven to 350°F. To make the streusel, mix 1/3 of the walnuts with 3 1/2 tbsp butter, 2 tbsp sugar, 2/3 cup flour and a pinch of salt and knead into crumbs. Place in the fridge and chill for 30 mins.
  • To make the batter, cream together the remaining butter and sugar with the vanilla extract and a pinch of salt. Stir in the eggs one at a time then fold in the flour, baking powder and cocoa powder. Mix well, then stir in the buttermilk. Drizzle the banana slices with lemon juice and fold into the batter with the remaining chopped nuts.
  • Transfer the batter to a 12-cup muffin pan, top with the streusel and bake for 25 mins. Remove from oven and cool on a wire rack.
  • Melt the chocolate in a bowl over a pan of warm water then transfer to a piping bag. Drizzle the chocolate over the muffins and allow to set for 30 mins before serving.