1.Preheat oven to 200°C (180°C fan-forced). Line four 12-hole (1 tablespoon/20ml) mini muffin pans with paper cases.
2.Sift flour and sugar into medium bowl; stir in remaining ingredients.
3.Divide mixture into paper cases. Bake about 10 minutes. Stand muffins in pans two minutes before turning, top-side up, onto wire racks to cool.
4.To make glacé icing, sift icing sugar into small heatproof bowl. Stir in oil and enough water to make a paste. Stir over small saucepan of simmering water until icing is spreadable. Divide icing evenly into four small bowls; tint each icing with one of the four food colourings. Spread cold muffins with icing.