Seashell of the Week #4

This week I'm cheating a little bit, but hey it's my game —my rules. This week's selection has had the shell removed, exposing the beautiful interior. As a child, we found these in numerous quantities and they were one of the favorite meals of my father. His technique was intense and very noisy, but the results were superb! Can you guess what it is?

Isn't it beautiful? BTW, no one has guessed last week's yet, so here is your chance to get two points towards the prize!