Line a 12-section bun tray with paper cake cases. Put the butter, sugar, flour, eggs and almond extract in a mixing bowl and beat for 1–2 minutes until light and creamy. Add the nuts and dried fruit and stir in until evenly combined. Divide the mixture evenly among the cake cases. Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 25 minutes until risen and just firm to the touch. Transfer to a wire rack to cool.
Put the nuts, sugars and food colouring for the marzipan in a bowl. Add the egg white and mix with a round-bladed knife until the mixture starts to cling together. Finish mixing the paste by hand until smooth and very firm. Lightly knead and shape into a thick sausage, 8 cm (3½ inches) long. Cut into 12 slices.
Spread ½ teaspoon jam on the centre of each cake, then place a marzipan slice on top.
Put the icing sugar in a bowl and add the measured water to make a thick smooth paste – the icing should hold its shape but not feel too firm. Gently spread the icing over the marzipan.
Knead and roll out the green and red ready-to-roll icing and use to make small holly leaves and berries. Press on to the tops of the cakes to decorate.