To prepare caramel: Cook sugar in a saucepan until the sugar turns golden brown. Remove saucepan from the heat and pour in water. Stir to dissolve the sugar until a caramel is formed. Set aside to cool completely.
Cream butter and sugar until light and creamy. Add the eggs, one at a time, beating well after each addition. Add in the essence. Fold in sifted dry ingredients and add in mixed fruits. Add the caramel to mix.
Turn batter into prepared cake pan and cover the top with a piece of aluminium foil. Steam over rapid boiling water for two hours or until cake is cooked through when tested with a wooden skewer.