Preheat your oven to 400°F.
Pat the chicken breast dry, season both sides generously with salt and pepper. Let it sit for a few minutes.
In a small bowl, gently muddle the garlic clove to release its aroma.
Heat 1 teaspoon olive oil in an oven-safe skillet over medium-high heat. Sear the chicken breast on each side for 2-3 minutes until golden brown. Remove the chicken and set aside.
In the same skillet, add the button mushrooms along with the muddled garlic and 1 teaspoon unsalted butter. Sauté for about 3 minutes until mushrooms begin to soften and take on a roasted aroma.
Return the seared chicken to the skillet with the mushrooms.
Meanwhile, toss the fresh green beans with 1 teaspoon olive oil, salt, and pepper on a baking sheet.
Place both the skillet (with chicken and mushrooms) and the baking sheet (with green beans) in the oven. Roast the chicken and mushrooms for 15-18 minutes, ensuring the chicken reaches an internal temperature of 165°F, while the green beans become crisp-tender.
Once cooked, remove from the oven. Let the chicken rest for a few minutes before slicing.
Plate the roasted chicken breast with a generous serving of garlic butter mushrooms and crispy green beans on the side. Serve warm.