Coat the bottom of a medium pot with olive oil and heat over medium heat until hot. Add in shallots and garlic and cook until softened about 3-5 minutes.
Add in chilis and cook for about 30 seconds more.
Add in cleaned mussels and deglaze with vermouth. Bring to a boil and cover.
Reduce heat to medium-low and steam until all the mussels have opened, about 4-6 minutes. If any mussels refuse to open, throw them out as they are most likely dead.
Remove mussels from the sauce and set aside.
Add in cream and simmer for 2-3 minutes to incorporate and warm the cream.
Stir in tarragon, parsley, and chives. Season to taste with salt and pepper.
Return mussels to the hot sauce and stir to coat.
Serve with sourdough toast and lemon wedges.
Video
Notes
*To clean the mussels, I just rinse them under cold water and scrub them with a clean scrubby. I also pull out the "beards" which are the hairy-looking stings on the side of the mussel. Not all mussels will have beards to remove.