Mix wine, shallots, and 4 cloves garlic in a large saucepan over medium heat. Bring to a simmer. Add mussels. Cook until shells open, 10 to 15 minutes.
Discard any unopened mussels. Drain the rest and place in a bowl.
Melt butter in a pan; add remaining garlic and heat until fragrant, 30 seconds to 1 minute. Add parsley, lemon juice, and lemon zest. Pour over the steamed mussels.
