Peel the garlic and shallots, and slice them very thin (make sure you remove the green stem from the garlic cloves before slicing).
Dice the fennel.
In a large saucepan, bring the butter to sizzle without coloration. Add the shallots, fennel, bay leaves (make an incision), and thyme. Deglaze with the white wine and add the mussels. Make sure to cover all the mussels with white wine. Add more wine if necessary.
Cover the saucepan to steam the mussels strongly.
Cook the mussels until they are all open.
Add the Crème Fraiche to make a “liaison” (sauce), then chili flakes, parsley, white pepper, and salt if necessary.