1. Preheat your oven to 400 F (200 C). In a large bowl, combine the chopped carrots with 2 tablespoons of olive oil, 1 tablespoon of chopped rosemary, 1 tablespoon of chopped thyme, 2 cloves of minced garlic, 1/2 teaspoon of salt, and 1/4 teaspoon of black pepper. Toss until the carrots are evenly coated. Place the chicken breasts on a baking sheet lined with parchment paper. Drizzle the remaining 2 tablespoons of olive oil over the chicken, then sprinkle with the remaining 1 tablespoon of rosemary, 1 tablespoon of thyme, 2 cloves of minced garlic, 1/2 teaspoon of salt, and 1/4 teaspoon of black pepper. Arrange the seasoned carrots around the chicken on the same baking sheet.

2. Place the baking sheet in the preheated oven. Roast for 25-30 minutes, or until the chicken is cooked through and reaches an internal temperature of 165 F (74 C) and the carrots are tender and slightly caramelized. Halfway through cooking, you can gently toss the carrots for even roasting.

3. While the chicken and carrots are roasting, place the peeled and quartered potatoes in a large pot. Cover them with cold water by about an inch. Add a pinch of salt to the water. Bring to a boil over high heat, then reduce heat to medium and simmer for 15-20 minutes, or until the potatoes are fork-tender.

4. Once the potatoes are tender, carefully drain them in a colander. Return the drained potatoes to the empty pot or transfer them to a large mixing bowl.

5. Add the 1/2 cup of milk and 1/4 cup of unsalted butter to the hot potatoes. Using a potato masher, mash the potatoes until they are smooth and creamy, or to your desired consistency. Taste and adjust seasoning with additional salt and pepper if needed.

6. Once the chicken and carrots are perfectly roasted and the mashed potatoes are creamy, it’s time to serve. Divide the mashed potatoes among plates, then top with a roasted chicken breast and a generous serving of the tender carrots. Garnish with fresh parsley, if desired, for a touch of color and freshness.