In a small skillet warm over high heat the coriander seed for a couple of minutes until fragrant. Remove from heat and set aside.
In a large skillet heat the olive oil over medium heat.
Season the chicken with salt and pepper and add them to the skillet. Brown them evenly on all sided, about 15 minutes.
Add the onions and cook stirring occasionally until soft. Add the garlic and cook for another minute.
Add the chicken broth, wine and the ground coriander and bring to a boil. Cover and cook over medium- low heat until the chicken is cooked through, around 15 minutes.
Transfer the chicken to a platter, cover and keep warm.
In a small bowl whisk together the mustard with the crème fraiche and tarragon. Whisk the mixture into the skillet and simmer the sauce over medium low until it thickens, 5 minutes .
Return the chicken and any liquids to the skillet and turn to coat.
Serve the chicken with crusty bread.