Remove the shells from the prawns and reserve any roe they are carrying. Bring water to a boil and whisk in the polenta and salt. Cook the polenta for 15 minutes on simmer, whisking periodically. Stir in the butter, half and half and cheese, then cook for another 5 minutes. Chill the filling in refrigerator. When the polenta is set, portion into small balls to fill your tortelletti. This dish can be equally delicious without the pasta—simply keep your polenta hot and serve with the prawns.
Slice the sunchokes into 1-inch pieces, cover with water in a stock pot and bring to a boil with the shallots. Once the water has reduced and the sunchokes are soft to the touch, add the cream and truffles or oil. Bring to a boil and carefully blend.
Sauté pancetta with a little canola oil until browned, then set aside.
Sauté spot prawns in butter and add prawn roe. This should take 2-3 minutes depending on the size of the prawn. Remove the cooked prawns, but save the pan and liquid the prawns were cooked in.
Cook pasta in boiling water. Once al dente, remove from water and toss with remaining spot prawn cooking liquid. Sauté the pasta until the liquid is reduced enough to coat the pasta and create a delicious sauce.
Spoon the sunchoke puree into bowls, top with pasta and spot prawns, garnish with fresh herbs, truffle peels or truffle oil, and pancetta.