1. Mix the chia or flax seeds with the 110ml water, and place in the fridge.

2. Take a very large saucepan and tip in the mixed fruit, glacé cherries, light brown sugar, black treacle, dairy-free margarine and 500ml water. Bring to the boil then simmer for 15 minutes, stirring from time to time.

3. When cooking time is up, carefully stir through the bicarbonate of soda, (the mixture will fizz and rise up the sides of the saucepan so make sure there is enough room to prevent spillages!). Set the mixture aside to cool completely.

4. Whist you are waiting for it to cool, grease a 22cm round or square baking tin, and line it with a double layer of baking parchment. Preheat the oven to 170°C (fan) / 325°F / gas mark 3.

5. When the mixture is cool, stir in the chia or flax seed mixture, (which should have turned very gloopy), and both types of flour. Mix well so that no lumps of flour remain.

6. Tip the mixture into your lined baking tin. Bake for 1 hour, then turn the oven down to 130°C (fan) / 275°F / Gas Mark 1 and bake for a further 45-55 minutes, or until an inserted skewer comes out clean. Leave to cool in the tin. To store until needed, wrap in a layer of baking parchment then a layer of foil and keep in an airtight tin or container.

7. A few days before marzipanning, feed the cake with brandy, amaretto or sherry by pricking all over with a cocktail stick then pouring over 4-6 tbsp of your chosen tipple. You can repeat this process three or four times for a boozier cake.