Cream together the butter or margarine
and sugar until light and fluffy, then gradually beat in the eggs and
wine. Fold in the flour and baking powder and mix until smooth. Spoon
into a greased and lined 18 cm/7 in cake tin (pan) and bake in a
preheated oven at 180°C/350°F/gas mark 4 for 1 1/4 hours until golden
brown and springy to the touch. Leave to cool in the tin for 5
minutes, then turn out on to a wire rack to finish cooling.