1. Sprinkle each chicken breast with 1/4 tsp of salt & pepper. In a large frypan or grill, heat the olive oil over medium-high heat. Add chicken & cook until cooked through about 11mins. Transfer to a plate, cover with foil to keep warm.
2. Pour the wine into the hot pan; cook, stirring until reduced by half for about 1min. Whisk in the cream, mustard & tarragon. Cook, whisking until thickened, about 2mins.
3. Pour any chicken juices into the sauce. Right before serving, drizzle the cream sauce over the chicken.