Broken mussel meat can be used as mussel willow, and the formula needs to be purchased from the prestigious quartermaster in Zan Gamache Spore Village, as follows:

1. First, players need to come to Zan Gamache in Outland.

2. Come to the spore village below.

3. You can see Myka, the quartermaster of Spore Village, at coordinates (17.9,51.1).

4, click on the interaction, you can buy the recipe: clam willow.