Preheat the oven to 180°C / 160°C Fan / Gas Mark 4. Line a 22cm loose bottom tart tin with greaseproof paper.
Place the chocolate in the mixing bowl. Blitz 5 sec/speed 7.
Scrape down, then melt 3 min/37°C/speed 2. Scrape into a separate bowl and set aside.
Add the beetroot, eggs, maple syrup and vanilla extract into the mixing bowl. Combine 30 sec/speed 5. Scrape down.
Add the cocoa powder, baking powder, salt, ground almonds, olive oil and dark chocolate and combine 20 sec/speed 4.
Pour the mixture into the prepared tin and bake for 30-35 minutes until a skewer inserted comes out clean.
You can also take it out slightly earlier and serve it as a gooey dessert. Remove from the oven, leave to cool in the tin for 10 minutes, then remove from the tin and serve warm or cold.