2 cups self-raising flour
1 ¼ cups caster sugar
½ cup vegetable oil
2 tablespoons finely grated orange rind
1/3 cup strained orange juice
½ cup buttermilk (See Tip)
2 tablespoons Dutch-processed cocoa powder
100g dark chocolate, chopped
½ cup pure cream
2 teaspoons honey
Grease a 22cm round springform pan (base measures 21cm). Line base and side with baking paper.
Combine flour and sugar in a large bowl. Whisk oil, rind, juice, buttermilk and eggs together in a large jug. Whisk into flour mixture until just combined.
Transfer 1 ½ level cups of mixture into a separate bowl with sifted cocoa. Whisk until combined.
Pour remaining mixture into prepared pan. Place large spoonfuls of chocolate mixture over the top. Using a spoon, swirl mixtures together three times only.
Cook in a moderately slow oven (160C) for about 45 to 50 minutes, or until a skewer inserted into centre comes out clean. Remove. Stand in pan for 15 minutes. Turn out onto a wire rack to cool completely.
To make chocolate glaze, place chocolate, cream and honey in a medium heatproof bowl. Sit bowl over a saucepan of simmering water. Stir until melted and smooth. Remove bowl.
Place cake on a serving platter. Drizzle over half the warm glaze. Cut into wedges. Serve with remaining warm glaze.