Preheat the oven to 170 C / Gas 3. Grease a large cake tin, about 20x30cm or similar.
First make the syrup: In a saucepan, bring all the syrup ingredients to the boil over medium heat. Reduce heat and simmer until the syrup is viscous but runny, about 12 minutes. Remove from the heat and allow to cool completely.
Beat the semolina, sugar and yoghurt. Dissolve the bicarb into the milk and add this to the mixture, beating all the
while. Add the grated lemon zest and mastiha and beat at medium-high speed for 5 minutes until the mixture is creamy. Pour into prepared cake tin.
Bake for about 1 to 1 1/2 hours or until set and lightly golden. If the cake browns before it sets, loosely cover the tin with aluminium foil and continue baking.
As soon as you remove the cake from the oven, pour over the cooled syrup, then sprinkle with the almonds. For best results, allow the syrup to completely soak in before slicing.