1. Preheat your oven to 375°F (190°C). Lightly grease a medium-sized baking dish and set aside.
2. Heat the olive oil or butter in a large skillet over medium heat. Add the chopped onion and cook until translucent, about 5 minutes.
3. Add the garlic and cook for another 1 minute until fragrant, stirring frequently to avoid burning.
4. Add the sliced mushrooms and cook until they release their moisture and start to brown, about 7-8 minutes. This step is key for developing flavor, so be patient here.
5. Sprinkle the flour over the mushroom mixture and stir well to coat everything evenly. Cook for 1-2 minutes to get rid of the raw flour taste.
6. Slowly pour in the chicken broth while stirring to create a smooth sauce. Then add the heavy cream, thyme, salt, and pepper. Simmer gently for 3-4 minutes until the sauce thickens slightly.
7. In a separate skillet, quickly sear the chicken pieces over medium-high heat for about 2-3 minutes per side, just until lightly browned but not fully cooked through. This adds a nice texture and seals in juices.
8. Transfer the chicken to the prepared baking dish. Pour the creamy mushroom sauce evenly over the chicken, then sprinkle the Parmesan cheese on top.
9. Bake uncovered for 20-25 minutes, or until the chicken is cooked through (internal temperature should reach 165°F or 74°C) and the sauce is bubbly and golden around the edges.
10. Remove from the oven and let rest for 5 minutes before serving. Garnish with fresh parsley for a pop of color and freshness.

I remember those early “Wednesday dinners” in college, where timing and multitasking were crucial. This bake fits perfectly into a hectic schedule because while the oven does its magic, you can prep a simple side or even fold laundry. It’s the kind of recipe that respects your time but delivers big on flavor.