Place the chicken breasts on a sheet pan, rub olive oil all over, and sprinkle salt and pepper. Set the oven to preheat at 350 F. Let the chicken sit while the oven preheats.
Roast the chicken for about 35-40 minutes till just cooked. Cool, and discard the bones and skin. Dice the chicken into bite size squares.,
Immerse broccoli in salted boiling water for 1 minute. Drain and dip into ice water. The broccoli will stay tender but crisp and retain its bright green color.
Prepare the dressing by whisking together the mayonnaise, wine, mustards, 1 tbsp salt and ½ tsp pepper.
Toss the diced chicken with sauce so that the pieces are nicely coated and moistened.
Combine the moistened chicken pieces with tarragon, broccoli and tomatoes and mix gently to combine.
Refrigerate for a few hours to allow the flavors to blend . Serve at room temperature.
Recipe by The Lady 8 Home at https://www.thelady8home.com/mustard-chicken-from-ina-kitchen-inafridays/