Preheat oven to 180 °C / 350 °F
Grease a square 25 cm / 10-inch cake tin
Place a small heatproof crockery bowl in a frypan half filled with water, so that the water comes half way up the sides of the bowl
Break up the 200g (7.1 ounces) carob and place in the bowl, avoiding any water getting in as it won’t stay smooth
Put over a low heat and it will melt while you are preparing the mixture
Sift the flours into a large mixing bowl and stir in the ground almonds and semolina
In a separate bowl, beat the eggs, add milk and continue beating
Slice the vanilla pod in half and scrape off the seeds with a small fork and add them to the liquid
Then add oil and liquer, mix
Finally, stir in the bicarb soda and baking powder (gently so as not to create too much fizz before it is in the oven)
Combine wet and dry ingredients and add the grated apple, stirring gently
Stir in the melted carob
Scoop the mixture into the pan and spread out evenly
Bake at 180 °C / 350 °F degrees for 45 minutes. Check after 30 minutes as cooking time varies between ovens. When a knife can be inserted and drawn out clean it is ready
Cool covered with a clean towel on the bench for 10 minutes