Step 1

Cook the beetroot in a large saucepan of boiling water for 40 minutes or until tender. Drain and cool slightly, then wearing gloves, peel skin from beetroot.

Step 2

Place beetroot in a food processor and whiz until smooth. Transfer to a large bowl and set aside to cool slightly.

Step 3

Preheat the oven to 180°C. Grease and line a 22cm x 10cm (1.5L capacity) loaf pan with baking paper.

Step 4

Add the chocolate, egg yolks, ginger, honey, oil, vanilla seeds and orange zest and juice to the cooled beetroot, and whisk to combine. Fold in flour, polenta, cocoa, baking powder, allspice, cinnamon and 1 tsp salt flakes.

Step 5

Whisk the eggwhites in a separate bowl until soft peaks form, then fold into the beetroot mixture until just combined. Pour batter into pan and bake for 1 hour or until a skewer inserted comes out clean. Cool in pan for 5 minutes, then transfer to a wire rack to cool completely.

Step 6

For the icing, using a stand mixer, beat butter until pale, scraping down sides with a spatula. Sift in icing sugar and beat for 1 minute or until combined. Add chocolate and beat for 2 minutes or until glossy.

Step 7

For drizzle, simmer all ingredients in a saucepan over low heat, stirring until thick and glossy. Cool slightly.

Step 8

Use a palette knife to spread icing over the cake. Spoon over the drizzle allowing it to run down sides of cake, then scatter over extra shaved chocolate to serve.