Grease a 2.5 litre/4 pint 8fl oz bundt tin (fir tree-shaped, if possible) very liberally with butter. In a mixing bowl, sift the flour and bicarbonate of soda together. Mix the butter and sugar ...
Beat in the eggs, one at a time, then mix in the yoghurt, vanilla and salt ... then turn the cake out onto a wire rack. Lift away the bundt tin and leave to cool completely.
Grease and flour a large (10 or 12-cup) bundt pan and set aside. In a large mixing bowl, stir together the cake and pudding mixes ... then add the butter and vanilla extracts.