Marinate the Chicken:

• In a gallon-sized Ziploc bag or a large bowl, whisk together the balsamic vinegar, 1/4 cup olive oil, finely chopped/pressed garlic (3 cloves), honey, Dijon mustard, Italian seasoning, 1 teaspoon salt, pepper, and red pepper flakes.
• Add the chicken breasts to the marinade, ensuring they are evenly coated. Seal the bag (removing excess air) or cover the bowl. Refrigerate overnight or for at least 4 hours.

Roast the Tomatoes:

• Preheat oven to 400°F (200°C).
• Place the cherry tomatoes and smashed garlic cloves (2 cloves) on a rimmed baking sheet. Drizzle with 2 teaspoons olive oil and season with salt and pepper. Toss to coat.
• Roast for 15 minutes, or until the tomatoes have burst, shriveled slightly, and are lightly caramelized on the edges. Discard the smashed garlic cloves (or save for another use). Set tomatoes aside.

Make the Mashed Potatoes:

• Boil Potatoes: Place the peeled and chunked potatoes in a large pot. Cover with cold water and season the water liberally with a couple of big pinches of salt. Bring to a boil and cook for 20 minutes or so, until the potatoes are fork-tender.
• Steep Milk: While the potatoes are boiling, heat the milk and one whole garlic clove in a small saucepan over medium-high heat until it just comes to a simmer (watch carefully to prevent boiling over). Once simmering, reduce heat to medium-low and let the milk and garlic steep for 15-20 minutes while the potatoes finish cooking. Once finished, discard the garlic clove.
• Make Garlic Butter: Heat the 4 tablespoons of salted butter in a medium saucepan (or the same small one, rinsed) over medium heat. Add the remaining 3 cloves of garlic (finely chopped or minced). Sauté for about 1 minute, until fragrant. Set aside.
• Mash Potatoes: Once the potatoes are fork-tender, drain them well. Return the potatoes to the pot. Add the steeped milk (without the garlic clove), the garlic butter mixture, sour cream (or Greek yogurt), 1 teaspoon salt, and pepper. Mash until the potatoes reach your desired consistency.
• Add Basil: Stir in the chopped fresh basil. Taste and season with additional salt and pepper, if needed. Keep warm.

Grill the Chicken:

• Remove chicken from marinade and discard excess marinade. Preheat your grill or grill pan to medium-high heat.
• Grill the chicken for 4-5 minutes per side, depending on the thickness, until cooked through (internal temperature reaches 165°F/74°C).
• Let the grilled chicken rest for 5-10 minutes before slicing.

Assemble and Serve:

• Slice the rested grilled chicken.
• Arrange a generous pile of the basil mashed potatoes on each plate. Top with slices of the grilled balsamic chicken.
• Scatter a spoonful of the garlic roasted tomatoes over the chicken and potatoes.
• Finish with a garnish of fresh basil leaves, a drizzle of balsamic glaze, a sprinkle of flaky sea salt, and freshly cracked black pepper to taste. Enjoy!