Add the shallots and garlic and season with a little salt. Cook for about 4 minutes, stirring often until soft.
Add the mussels, wine, thyme and bay leaf. Cover and cook until steam begins to escape from under the lid.
Spin the lid to engage the Vapor Seal then immediately reduce the heat to low. Cook for 4 minutes. Lift the lid and give the mussels a quick, but gentle stir. If the mussels are not open, replace the lid and cook for another minute.(Do not over cook or they will be crumbly and tough.)
Discard the hot water from the bowl. Use a slotted spoon to transfer the mussels to the warm bowl.
Discard any unopened mussels. Cover loosely with foil.
Stir the parsley and tarragon into the broth and season with salt and a few grinds of pepper.
Pour the broth over the mussels and serve immediately.