Heat the oven to 400°F with a rack in the lower-middle position. Using paper towels, pat the chicken dry, then season on all sides with salt and pepper. Set aside.

In a large (at least 7-quart) Dutch oven over medium, melt 1 tablespoon butter. Add the shallots and garlic and cook, stirring occasionally, until lightly browned, about 5 minutes.

Stir in the red pepper flakes, apricots and saffron, then cook until fragrant, about 30 seconds. Add the wine and bring to a simmer. Lay the thyme sprigs on top, then place the chicken breast down in the pot.

Cover and bake until the thickest part of the breast reaches 160°F and the thighs reach 175°F, 55 to 65 minutes.

Using tongs inserted into the cavity, carefully transfer to a baking dish, turning it breast up. Let rest for 15 minutes.

While the chicken rests, remove and discard the thyme sprigs from the pot. Bring the cooking liquid to a simmer over medium and cook until thick enough to lightly coat a spoon, about 10 minutes.

Off heat, add the remaining 4 tablespoons butter and lemon juice, then stir until the butter melts. Taste and season with salt and pepper.

Transfer the chicken to a cutting board. Remove the legs from the chicken by cutting through the hip joints.

Remove and discard the skin from the legs, then separate the thighs from the drumsticks by cutting through the joints. Remove the breast meat from the bone, remove and discard the skin, then cut each breast half crosswise into thin slices.

Arrange the chicken in a serving dish. Stir the tarragon into the sauce, then spoon the sauce, apricots and vegetables over and around the chicken.