Preheat your oven to 180 deg C and grease a 22cm baking tin.

Mix the yoghurt, olive oil, juice and eggs until well combined.

Combine the flour, sugar, baking powder, salt and lime zest.

Melt the chocolate

Add the olive oil and cocoa powder

Stir to combine, making sure there are no lumps

Preheat your oven to 170°C. Grease a 22cm springform tin with a little oil and line the base with baking parchment.

Measure and sift the cocoa powder into a bowl or jug and whisk in the boiling water until you have a smooth, chocolatey, still runny (but only just) paste. Whisk in the vanilla extract, then set aside to cool a little.

In another smallish bowl, combine the flour with the bicarbonate of soda and pinch of salt.