Cook beetroot in a small saucepan of boiling water for 45 minutes or until tender. Drain, reserving 2 tablespoons of the cooking liquid. Process beetroot and reserved liquid until smooth. You should have 1 cup beetroot purée.

Preheat oven to 160°C/325°F. Grease a 22cm (9-inch) springform pan; line base and side with baking paper.

Stir chocolate and butter in a small saucepan over low heat until melted and smooth.

Whisk eggs, extract, sugar and ground hazelnuts in a large bowl until combined. Add chocolate mixture and beetroot purée; whisk to combine. Pour mixture into pan; cover with foil.

Bake cake for 1 hour 10 minutes or until cooked around the edge with a slight wobble in the centre. Lift up edge of foil to release steam. Refrigerate cake for at least 3 hours or overnight.

Make candied beetroot. Stir sugar and the water in a small saucepan over medium heat until sugar dissolves. Bring to the boil. Add beetroot; cook for 20 minutes or until beetroot slices become slightly translucent and syrup thickens. Using two forks, transfer beetroot from syrup to a baking-paper-lined oven tray to cool. Reserve 1 cup of the syrup; stir in juice.

To make sweetened crème fraîche, whisk ingredients together in a small bowl until soft peaks form.

Place cake on a platter; dust cake edges with cocoa. Spread top of cake with sweetened crème fraîche. Top with candied beetroot and drizzle with reserved syrup.