Baked Lotus Root Cake

recipe adapted from here
Ingredients

150 gm young lotus root, finely grated
220 gm butter/margarine
130 gm caster sugar
1/8  tsp salt               
5 eggs separated
285 gm plain flour     
1 tsp baking powder
3/4 tsp vanilla
75 gm raisins      
 Method

1. Chop up the sultanas and lightly coat with some flour from the above 285 gm.
2. Lightly flour and grease an 8 inch square or round tin.  Set aside.
3. Grate the young lotus root and gently squeeze out liquid.  Do not squeeze completely dry, but moist enough.
4. Sift the flour with the baking powder and salt.  Set aside.
5. Cream butter with sugar till light, creamy, thick and fluffy.
6. Beat in egg yolks one at a time, mix well.
7. Add in vanilla and grated lotus root till well combined.
8. In another bowl, beat egg whites till stiff but not dry.
9. Fold the egg whites into the lotus root mixture.  Mix thoroughly, scraping from the sides and bottom of the mixing bowl.
10. Finally add in the chopped and floured sultanas.
11. Pour batter into prepared tin, bake in preheated oven @ 180 deg C for about 70 mins. or till skewer inserted comes out clean.
12. Allow cake to cool in tin for about 10 mins. before turning out to cool on wire rack.