1.Preheat oven to 220°C. Grease a 20cm x 30cm rectangular pan. Line base and long sides with baking paper then a strip of foil, extending paper 5cm over sides.
2.Trim pastry to fit base of pan and prick all over with a fork. Bake 10 minutes. Cool. Reduce oven temperature to 180°C.
3.Sift flour, spices and soda into large bowl and stir in remaining ingredients. Spread mixture into pan; smooth surface. Bake about 25 minutes. Cool slice in pan.
4.Meanwhile, to make cream cheese frosting, beat ingredients in a small bowl with electric mixer until smooth. Spread slice with frosting before cutting.