Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Wash and dice the Yukon Gold potato into 1-inch cubes, and finely mince the garlic clove.
In a small bowl, whisk together the olive oil, Herbes de Provence, minced garlic, sea salt, and black pepper.
Toss the potato cubes with half of the herb-oil mixture and spread them in a single layer on the baking sheet.
Roast the potatoes for 15 minutes.
While potatoes roast, brush the remaining herb-oil mixture onto the chicken breast.
Remove the baking sheet from the oven, slide the potatoes to one side, and place the chicken breast on the other side.
Return the sheet to the oven and roast for another 18-20 minutes, or until the chicken reaches an internal temperature of 165°F.
While the chicken finishes, steam the green beans in a steamer basket over boiling water for 5-6 minutes until tender-crisp.
Plate the roasted chicken and potatoes alongside the green beans, finishing with a fresh squeeze of lemon juice over the entire dish.