Preheat the oven to 400 degrees. Using a wooden spoon, combine the butter, mustard, half the garlic, the lemon juice, zest, rosemary, salt, and pepper in the mixing bowl until well blended. Loosen the chicken skin by lifting it gently from the flesh with your fingers. The skin will lift quite easily. Reserving 2 tablespoons, spread the herbed butter under the skin. Lightly spread the remaining butter over the chicken pieces. Put the onions, carrots, turnip, and the rest of the garlic into the roasting pan. Place the chicken on the bed of vegetables. Roast for 40 to 45 minutes, until the chicken is golden brown and cooked through.
Serve 2 pieces of chicken with roasted vegetables per person.
Recipe courtesy of Abagail Kirsch, author The Bride & Groom's First Cookbook