Step 1:
1. grease a 28cm x 18cm slice tray. Step 3:
2. measure dry ingredients into a mixing bowl. Step 5:
3. melt margarine over a low heat. Step 7:
4. pour melted margarine into the dry ingredients with the beaten egg. Mix well. Step 9:
5. spread mixture over the base of the slice tray. Step 11:
6. bake in a moderate (1800) for 20 minutes or until just firm to the touch. Step 13:
7. sift icing mixture and cocoa into a bowl, stir in margarine and milk to give a thick paste. Step 15:
8. spread with icing as soon as the slice comes out of the oven. Leave slice in the tin. Step 17:
9. stand in the fridge for 10 minutes before cutting into squares.