Chocolate and marshmallow mini egg traybake

Method

1. Heat the oven to 180°C/160°C fan/gas 4. To make the cake, whisk the butter and sugar in a mixing bowl using an electric hand mixer for 1-2 minutes until light and creamy. Mix the cocoa powder and water in a cup to combine, then whisk into the butter and sugar along with the flour, baking powder and eggs until well combined. Stir in the chopped mini eggs, then pour the mixture into the prepared tray. Bake for 30-35 minutes until a skewer pushed into the centre comes out clean. Leave to cool completely in the tray.
2. To make the ganache, put the chocolate in a heatproof bowl, heat the cream in a pan and, just before it starts to boil, pour the hot cream over the chocolate. Leave for a minute, then stir slowly so the chocolate melts into a silky ganache. Pour this over the cooled cake (still in its tray). Chill the traybake in the fridge for an hour or so to set the ganache.
3. Meanwhile make the marshmallow icing: mix the egg whites, sugar and orange juice in a bowl. Put the bowl over a pan of simmering water (don’t let the bowl touch the water) and whisk using an electric hand mixer until the mixture is shiny and thick (5-7 minutes). Take off the heat, add the marshmallows and stir with a wooden spoon until you have a thick, creamy, sticky icing.
4. Spread the icing over the chilled, set ganache using a palette knife, then let the icing cool and set for 1 hour (see Make Ahead). Just before serving, top with the remaining whole mini eggs. Cut into squares.