Preheat your oven to 400°F (200°C).
Trim the woody ends off the asparagus and place them on a parchment-lined baking sheet.
Drizzle the asparagus with 0.5 tablespoons of olive oil and season with half of the salt and pepper.
Roast the asparagus for 12-15 minutes until tender-crisp and slightly charred.
While the asparagus roasts, season the chicken breast with the remaining salt and pepper.
Heat the remaining 0.5 tablespoons of olive oil in a large skillet over medium-high heat.
Sear the chicken for 5-7 minutes per side until fully cooked through and golden brown, then remove from the pan and set aside.
In the same skillet, add the sliced mushrooms and sauté for 4-5 minutes until they release their moisture and turn brown.
Add the minced garlic and thyme to the mushrooms, cooking for 1 minute until fragrant.
Pour in the chicken broth and lemon juice, scraping up any browned bits from the bottom of the pan.
Simmer the sauce for 2-3 minutes until slightly reduced, then return the chicken to the pan to coat it in the sauce.
Serve the garlic mushroom chicken immediately alongside the roasted asparagus.