Prepare the tin

• Grease a 20 cm springform cake tin and line it with baking paper.
• Preheat the oven to 160 °C.

Blitz the orange with the butter

• Place the quartered orange and the butter in the Thermomix bowl.
• Blitz for 7 seconds at speed 8.

Mix the batter

• Add the eggs, sugar and self-raising flour.
• Mix for 20 seconds at speed 4, scraping down the sides if needed.

Bake the cake

• Pour the batter into the prepared tin and smooth the top.
• Bake for 55 minutes at 160 °C, until a skewer comes out clean.

Cool and serve

• Leave the cake to cool in the tin for a few minutes, then turn out onto a rack.