Make the cake:

1. In a very large bowl, mix the currants, raisins, cherries, apricots and mixed peel with the brandy; cover the bowl and leave it in a cool place overnight.
2. Lightly grease a 9″ springform pan and line the sides and bottom with parchment paper—Preheat the oven to 275° F.
3. In a large bowl, combine the flour, nutmeg, mixed spice, butter, sugar, eggs, chopped almonds, black treacle and citrus zest. Beat well to mix thoroughly. Fold in the soaked fruits.
4. Spoon the mixture into the prepared pan and spread out evenly with the back of a spoon. Cover the top of the cake loosely with a double layer of parchment. Bake in the preheated oven until the cake feels firm to the touch and a skewer inserted into the centre comes out clean (4¼ -4¾ hours). Allow the cake to cool in the tin.
5. When cool, pierce the cake at intervals with a fine skewer and ‘feed’ with a bit of brandy. Once the cake is completely cold, leave the lining paper on the cake, wrap in a double layer of parchment paper and again in foil; store in a cool, dry place for up to three months, feeding at intervals with more brandy.

Make the Almond Marzipan:

1. In the bowl of a food processor, pulse the ground almonds and confectioners’ sugar until combined and any lumps are broken up. Add the almond extract and water and pulse to combine. Add the egg white and process until a thick dough is formed.
2. Turn out onto a work surface and knead a few times. Then, on a surface lightly dusted with confectioners’ sugar, roll it out into a circle ¼” thick and ½” wider than the diameter of the cake plus the depth of the sides. Sprinkle additional confectioners’ sugar if the marzipan is sticking at any point.
3. Brush the top and sides of the cake with the strained jam, then leave a few minutes to set. Turn the cake upside down onto the centre of the circle of marzipan and wriggle it gently so the top sticks firmly.
4. Carefully turn the cake right way up and gently press the sides of the marzipan into position. Trim any excess around the bottom.

Make the marshmallow fondant:

1. In a large glass bowl, microwave the marshmallows and water on high for one minute until the marshmallows are puffy. Stir them with a rubber spatula until melted and smooth, microwaving for a further 30-45 seconds if lumps remain. Add a few drops of blue gel food colouring, going a little darker than you would like the final fondant to be. 
2. Stir in the confectioners’ sugar until the mixture is too stiff to move. Scrape it onto a surface dusted with confectioners’ sugar. Dust your hands with confectioners’ sugar and knead the mixture until it’s smooth and elastic. Knead in a bit more food colouring if the fondant is lighter than you would like.
3. Roll out the fondant into a large circle 1/8″ thick and ½” greater in circumference than the diameter of the cake plus the sides; drape over the marzipan-covered cake, smooth with your hands (and a fondant spreader if you have one). Trim the bottom with a sharp knife.

Decorate the cake:

1. Lightly grease your hands with vegetable shortening. Using your fingers, smooth a bit of shortening into the cavity of your chosen mould to prevent the fondant/gum paste from sticking.
2. Using your greased hands, mix the gum paste and fondant to form a smooth paste. Break off a small piece and press it firmly into the mould cavity (keep the remainder covered to prevent it from drying out). Using a lightly greased palette knife, trim any excess, then use your fingers to ensure the edges of the cavity have clean margins. Freeze the mould for 10-15 minutes before turning out the figure (deer, tree or snowflake). 
   I found this YouTube video invaluable in explaining it well. 
3. Use a few spoons of confectioners’ sugar mixed with a bit of water to make a thick paste, or if you have some leftover Royal Icing from decorating sugar cookies, use a little of that. Apply a tiny dab on the back of the figures before attaching them to the cake. Use the brushes to apply icing around the figures to create grass and landscape. Use the small round piping tip to create branches around the edges of the cake and a dry brush to create a feathery effect.