Peal the garlic and shallots 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 but with no 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 the white wine. Add more wine if necessary.
Cover the saucepan to strongly steam the mussels.
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.