Season and Sear Chicken:
Pat chicken thighs dry and season with salt, pepper, and paprika. Heat olive oil in a large skillet over medium-high heat. Sear chicken skin-side down for 5–6 minutes until browned, then flip and cook 2–3 minutes more. Remove and set aside.
Sauté Mushrooms and Aromatics:
Reduce heat to medium. Add butter to the same pan, then add mushrooms and cook until browned, about 5–6 minutes. Stir in onion and garlic, cooking another 2 minutes until fragrant.
Deglaze and Simmer:
Pour in chicken broth, scraping up any browned bits. Stir in cream, Dijon mustard (if using), and thyme. Simmer for 2–3 minutes until slightly thickened.
Return Chicken to Pan:
Nestle chicken thighs back into the skillet, skin-side up. Reduce heat to low, cover, and simmer for 20–25 minutes until chicken is cooked through (165°F internal temp).
Finish and Serve:
Remove from heat. Garnish with fresh parsley and serve warm with your favorite side.