For the syrup: zest and juice the lemon. Place the water, sugar, lemon zest and juice in a pan and bring to the boil. Simmer for 5 minutes and then pass the liquid through a sieve.
For the almond sponge: preheat the oven to 180°C.
Melt the butter. Split the vanilla pod in half and scrape out the seeds.
Beat together the yogurt and the sugar. Add the butter, ground almonds, vanilla seeds, orange flower water and the egg.
In another bowl, mix together the semolina and the baking powder. Add the ground almond mixture and combine. Pour the mixture into rectangular moulds and bake in the oven for 20 minutes.
Remove from the oven and pour the syrup over the cakes. Allow to the cool and then remove the rectangular moulds.
Peel the grapefruits, making sure to remove all of the pith. Remove the segments and cut into small pieces.
For the drizzle: zest and juice the lime. Place the water and sugar in a small pan and heat until the sugar melts. Add the olive oil, lime zest, lime juice and the thyme sprigs.
Top each almond and orange flower sponge with a layer of grapefruit and then finish with a drizzle of the olive oil, lime and thyme dressing.
«If you do not have individual rectangular moulds, feel free to make one large cake which can be cut into individual portions once cooked. Increase the cooking time to 45 minutes in this case.»