1 ½ cups self-raising flour
1 cup caster sugar
1/3 cup cocoa powder
½ teaspoon salt
2 teaspoons vanilla essence
1 tablespoon white vinegar
½ cup vegetable oil
1 cup warm water
¾ cup bought chocolate frosting (See Tip)
3 x 26g Cadbury Curly Wurly chocolate bars, chopped
Remove base from a 20cm round springform pan (base measures 19cm). Tear off a sheet of baking paper larger than the base. Invert the base, then place paper over top. Without trimming the baking paper, place the side of the pan over the baking paper and secure the clip on the side of pan. Do not grease.
Sift flour, sugar, cocoa and salt into prepared pan.
Make three evenly-spaced holes in mixture. Pour vanilla into one hole, vinegar into another and oil into the remaining hole. Pour 1 cup warm water over top. Stir with a spoon until all ingredients are well combined, scraping around edge and over base, taking care not to tear the baking paper. Place pan on an oven tray.
Cook in a moderately slow oven (160C) for about 40 minutes, or until cooked when a skewer inserted into the centre comes out clean. Remove from oven. Cool completely in pan.
Remove side of pan. Turn cake onto a wire rack. Remove base of pan. Peel away baking paper. Transfer cake, top-side up, to a serving plate.
Spread with frosting. Decorate with chocolate bars.