1. For the savoury shortbread, mix all the ingredients in a food processor. Sprinkle some flour onto your work surface and knead the mixture into a roll with a diameter of 5cm. Cover the role with cling film and leave to rest for at least 30 minutes.
2.Meanwhile, preheat the oven to 180°C. Unwrap your roll and cut it into slices of about 1cm Place the slices on baking paper and bake the pieces for 10 to 15 minutes. Let them cool down on a cooling rack.
3. Meanwhile, prepare the avocado mousse. Peel the avocado, cut it into small pieces and sprinkle with lime juice. Mix the avocado with the mackerel, coriander and Alpro Soya Original Drink until smooth. Add a pinch of salt, cayenne pepper and additional lime juice to your own taste.
4. Scoop the mousse on top of the cooled shortbread and garnish with coriander and cayenne pepper.