Pat chicken thighs dry with paper towel and trim off excess fat. Combine the onion powder, garlic powder, herbs, salt and pepper. Coat the chicken evenly with the combined seasoning.
Heat 1 tablespoon of oil a large pan or skillet over medium-high heat and sear chicken thighs in batches until browned on each side and no longer pink in centre (about 8 minutes each side, depending on thickness). Add remaining oil if needed for second batch. Transfer to a plate; set aside and keep warm.
To the same pan or skillet, melt the butter and add the mushrooms. Season with salt and pepper and cook until soft (about 3 minutes). Add the garlic, parsley, thyme and rosemary; sauté until fragrant (about 1 minute).
Stir in cream, bring to a simmer, then reduce heat and continue cooking until sauce has thickened slightly. Stir in the parmesan cheese and allow it to melt through the sauce for a further 2 minutes, while occasionally stirring.
Return chicken to the pan. Taste test and season with salt and pepper to your taste. Garnish with fresh parsley. Serve immediately.
Notes
*You CAN use fresh herbs if you have them! 2 teaspoons each of fresh herbs is fine. If you don't like Thyme or Rosemary, substitute with Basil and Oregano, or use Tarragon. **Heavy or thickened cream is used for low carb/high fat purposes. If counting calories and/or fat macros instead, use evaporated milk, reduced fat cream or half and half.
For a dairy free option, I find Cashew milk the best in flavour. You can also use almond milk or rice milk. Thicken with a cornstarch slurry (2 teaspoons cornstarch mixed with 1 tablespoon water, mix to blend well and add to the sauce, stirring quickly, until thickened)
Optional: For even more amazing flavour, add in ⅓ cup dry white wine with your mushrooms and cook it down to half before adding in your garlic and cream!