Linguine con Vongole

If using fresh clams, put cockles in bowl of iced salted water and let sit for ½ hour. Drain.

Bring a large pot of water to boil for the pasta. 

Put the clams in a large pot over medium heat. Add about ½ cup water and steam until shells open and release their clam juice (or liquor, as it's called), a few minutes, then turn off heat.

In a large pan, add EVOO, a few turns of the pan, add anchovies over medium-low heat and gently stir until anchovy melts. Add garlic, thyme, lemon zest, chili paste or chile flakes, and stir. Add about 1 cup wine, turn up the heat and reduce sauce by half. 

Add pasta to pot of boiling water and salt it. 

Remove about ¾ clams from their shells, adding back to their liquor in the pot. Transfer the clams in their shells to a plate. 

Squeeze lemon halves into sauce, add butter and half the parsley. Add clam liquor and shelled clams to pan sauce. 

Drain pasta just shy of al dente, then add to sauce and finish cooking. Add celery tops or micro celery and garnish with reserved clams in shell. Finish with remaining parsley.