Preheat the oven to 150C/170C Fan//Gas 3. Grease and line the base of a 23cm (9 inch) springform or loose bottom cake tin.
In a large heatproof bowl, blend the boiling water with the bicarbonate of soda. Add the molasses and sugar and whisk well until all the sugars dissolve, set aside.
In a large bowl sift together the flour and all the remaining dry ingredients.
Stir the oil and eggs into the molasses mixture. Tip the flour into the molasses mixture and stir with a balloon whisk until fully incorporated and smooth.
Pour the batter into the prepared tin and bake for 30-35 mins or until a knife inserted in the centre comes out clean.
Transfer the cake to a wire rack and leave to cool in the tin for 10 minutes. Run a knife around the tin before removing the ring. Then leave the cake to cool completely.
To make the cream cheese frosting, rub the butter into the icing sugar until it resembles breadcrumbs. Add the chilled cream cheese and beat until smooth. Add the vanilla bean extract and beat again.
To serve, place the cake on a plate and spread the cream cheese frosting over the top with a palette knife. Decorate with dried orange slices, or frosted cranberries.
Store for up to 3 days uncovered in the fridge, but serve at room temperature. Not suitable for freezing.