1. Pat chicken dry and season all over with 1/2 teaspoon each salt and pepper. Heat oil in a high-sided skillet or Dutch oven over medium until shimmering. Add chicken, skin side down, and cook without moving until skin is golden brown and very crispy, 8 to 10 minutes. Flip and continue to cook until well browned but not cooked through, 5 to 10 more minutes; transfer to a plate.
2. Pour off all but 2 tablespoons fat in skillet, then add onions and cook, stirring frequently, until lightly browned, about 2 minutes. Stir in broth and mustard, breaking up any clumps. Increase heat to high and bring liquid to a boil, scraping up browned bits from bottom of pan.
3. Return chicken, skin side up, to skillet along with any accumulated juices and return liquid to a boil. Reduce heat to medium-low and simmer gently, uncovered and without stirring, until chicken is cooked through and very tender, 25 to 35 minutes.
4. Transfer chicken to a clean plate and set aside. Stir peas and tarragon into skillet and cook until peas are warmed through but still bright green, about 2 minutes; season with salt and pepper to taste. Transfer vegetables and sauce to a serving platter, top with chicken, and sprinkle with more tarragon before serving.
Source: Hannaford fresh Magazine, March-April 2023