Heat 1 tablespoon of oil or butter in a skillet over medium heat.
While the skillet heats, pat the chicken breasts dry and season both sides evenly.
Place the chicken in the skillet and sear for 6-8 minutes per side, or until fully cooked.
Remove from the skillet and set aside.
In the same skillet, add the remaining 2 tablespoons of oil or butter.
Once melted, add the mushrooms and cook for about 8 minutes, until tender.
Stir in the minced garlic and cook for an additional 2-3 minutes, until fragrant.
Add the spinach and gently stir until wilted.
Pour in the chicken broth, heavy cream, and grated Parmesan, stirring to combine.
Bring the mixture to a gentle simmer, then return the chicken to the skillet.
Cook for an additional 10 minutes, allowing the flavors to come together.
Serve warm over potatoes, pasta, or enjoy on its own.