Preheat the oven to 180°C.
Pound the spice mix ingredients into a smooth powder using a pestle and mortar.
Bake the potatoes for 50 minutes until soft and let them cool.
Sauté garlic and prawn shells in olive oil, add tomato purée and 300ml water, simmer for 10 minutes, then strain.
Mash potato flesh and combine with flour, salt, and egg to form a dough.
Roll dough into 1cm thick ropes and cut into 2cm lengths.
Sweat onion and garlic in oil, add spices, then stir in prawn stock and reduce before whisking in butter.
Boil gnocchi in salted water for 3 minutes until they float.
Stir parsley and crab into the sauce and toss with the drained gnocchi.