Place a large frying pan on a medium heat and add half of the butter.
Cook the samphire for a few minutes until softened and set aside.
Add the shrimp/prawns when the butter gets hot and cook for a few minutes until opaque and set aside.
Cook the pasta in a large pan of generously salted water according to packet instructions.
Meanwhile, add the remaining butter and fry the garlic for a minute or two until fragrant.
Pour in the white wine and let it simmer for a few minutes until reduced by half.
Add the tomato puree and anchovy paste and simmer for a few minutes until reduced a little.
Stir the squid ink (if using) into the fish stock and pour into the pan and simmer for 10 minutes.
Drain the cooked pasta, ensuring you reserve a little pasta water. (Note 8)
Stir in the lemon juice and zest then toss the cooked pasta and shrimp/prawns in the sauce. Add 1-2 tablespoons of the reserved pasta water if a little extra moisture is needed.
Serve immediately, topped with optional samphire.