Add the lemon to a saucepan and cover with water. Bring to the boil and simmer over a low heat for 40 minutes. Drain the water and allow the lemon to cool.
Preheat your oven to 180°C. Grease and line a round cake tin with baking paper.
Cut the cooked lemon in half and remove the pits. Add this to a food processor along with the eggs, greek yoghurt and olive oil. Process into a thick paste making sure it’s nice and smooth.
Add the dry ingredients to a bowl and mix together. Add the lemon mixture to the dry ingredients and mix until combined. Pour into cake tin and bake for 50 minutes until golden brown and set.
You’ll know it’s done when the top has gone golden brown and the egg has puffed up.