In a large skillet, heat oil over medium heat. Add chicken and brown both sides, about 3 minutes per side.
Pour chicken broth over chicken. Add mustard, butter, tarragon, lemon zest, and pepper (no need to stir). Cover and simmer for 30 minutes.
Remove chicken to a serving dish and cover to keep warm.
Add cream and wine to pan and bring to a boil. Reduce sauce by about one third. Reduce heat to bring to a simmer and add lemon slices. Simmer for 5 minutes. Add salt and pepper to taste.