For 4 people :
A week before :
1) Prepare the sauce. Peel the garlic and crush the garlic press. Rinse sprig of tarragon, pat dry with paper towels. The pluck and coarsely chop the leaves.
2) In a wide-mouth bottle (bottle type of fruit juice) perfectly washed and dried, put the garlic, tarragon, oil, dry white wine, pastis, herbes de Provence and pepper. Close the bottle and shake vigorously. Keep in fridge, shaking every day.
The same day :
3) Clean the mussels by brushing under running water, soak, distribute in a large skillet (dish paella kind) and place it on hot coals.
4) Cook the mussels 8 to 10 minutes, shaking the pan occasionally, until they open. Then pour the sauce over the mussels and continue cuissin 3 to 5 minutes, shaking from time to time, the stove again.
5) Serve mussels immediately after eliminating those that are not open with buttered bread