Put the saffron threads into a glass with a couple of tablespoons of warm water. Leave to infuse and melt. 

Remove the tails, peel and devein the shrimp and set aside. 

Put the shells only in a saucepan with a cup of water and a teaspoon of salt. Bring to a boil, turn the heat down to low and then simmer the shells for 15 minutes to make a shrimp stock.

Strain the broth into a bowl and add the soaking saffron to it.

Put a pot of water on to boil for the pasta. Add salt once it starts to boil. 

Sweat the shallots in a skillet over a low heat with the butter and some pink peppercorns. Once the shallots start to soften add the saffron broth. Turn up the heat, bring to a boil for a couple of minutes. 

Turn the heat down and add the shrimp and cook for 5 minutes, flipping half way through the cooking. 

Add the heavy cream and mix it into the sauce. Season to taste.

Cook the pasta to al dente according to the package directions. When the pasta is cooked, save a little of the cooking water and drain. Add the pasta to the sauce. 

Mix everything together and if the pans seems dry add a little pasta cooking water. Remove from the heat and serve immediately sprinkled with chopped parsley.