In a large saucepan, add your pasta to salted, boiling water. Cook the pasta as per packet directions.
Put your frypan on high heat and melt the 15g of butter. Once melted add your prawns and sprinkle them with the salt. Stir these for about four minutes until they are nice and pink and cooked through. Remove the prawns to a plate.
Add the frypan back to the heat and heat on medium. Add the 35g of butter, heat until melted, add garlic and cook stirring for about 3-4 minutes. You don't want the garlic to brown, you just want to infuse it's flavour into the butter.
Add wine, and cook the mixture until the wine has almost completely evaporated.
Add the chicken stock, cream, parmesan, parsley, pepper and garlic powder into the pan. Bring to the boil and let this bubble for about 2 minutes.
Mix the cornflour and the water together well, add to the sauce and immediately mix together well. Add the prawns back in to heat up.
Drain your cooked pasta well and add to the sauce. Toss to combine well. Serve with another light dusting of parmesan.