Heat the oven at 200°C (th 6).
Grease a 23cm diameter cake tin.
Knead the flour and butter until the dough is completely crumbled, add the fruit and the sugar, then mix all together.
Sprinkle the bicarbonate of sodium into the milk and add the vinegar.
The milk will begin to froth in about 2 minutes.
Add this still frothing mixture to the preparation of butter, sugar and dried fruit.
Pour into the tin and cook for 30 minutes.
Lower the oven to 170°C (th 3) and continue cooking for 1 1/2 hours until the cake is firm to touch.
Leave to cool down and remove from the mould.