Preheat your oven to 425°F.
Pat the chicken breast dry and season both sides with salt and pepper.
In an oven-safe skillet, heat the olive oil over medium-high heat. Sear the chicken breast for 2-3 minutes on each side until browned.
Transfer the skillet to the oven and roast the chicken for about 12-15 minutes, or until the internal temperature reaches 165°F.
While the chicken is roasting, heat a small pan over medium heat and melt the butter. Add the minced garlic and sauté for 30 seconds until fragrant.
Add the sliced mushrooms to the pan and cook until soft, about 3-4 minutes. Stir in the heavy cream and allow to simmer for an additional minute. Season with a pinch of salt and pepper.
On a separate baking tray, toss the broccoli florets with a drizzle of olive oil, salt, and pepper and roast in the oven during the last 10 minutes of the chicken's roasting time until crispy.
Once everything is cooked, plate the chicken breast, spoon the creamy garlic butter mushrooms over the top, and serve with a side of crispy roasted broccoli.