Pat the chicken thighs dry and season both sides generously with garlic powder, salt, and pepper. Use your hands to press the seasoning into the meat — this helps it stick and creates better flavor throughout.
Heat the olive oil in a large skillet over medium heat until it shimmers. Lay the chicken thighs smooth side down in the pan, leaving space between each piece so they sear properly rather than steam.
Press the chicken gently with your spatula to ensure good contact with the pan, then let them cook undisturbed until deep golden brown. You'll hear the sizzling slow down as the moisture evaporates — that's when you know they're ready to flip.
⏱ 4 min
Flip the chicken and press lightly again. Cook just until the second side firms up — it doesn't need to be fully cooked since it'll finish in the sauce.
⏱ 2 min
Transfer the chicken to a clean plate and tent loosely with foil. Don't clean the pan — those golden bits stuck to the bottom are pure flavor.
Lower the heat to medium-high and add the butter to the same skillet. Once it's melted and foaming, add the onions and cook until they start to soften. Add the mushrooms and spread them in a single layer as much as possible.
⏱ 1 min
Let the mushrooms cook without stirring until they release their moisture and turn golden brown. Stir occasionally to get even browning, and scrape up any browned bits from the chicken — they'll dissolve and add incredible depth to your sauce.
Sprinkle the flour over the vegetables and stir constantly to coat everything evenly. Cook until the raw flour smell disappears and the mixture looks slightly toasted.
⏱ 1 min
Pour in half the broth while stirring vigorously to prevent lumps from forming. Once smooth and well incorporated, gradually add the remaining broth, stirring constantly until the mixture thickens slightly.
Whisk in the sour cream and Dijon mustard until completely smooth. The mustard adds a subtle tang that balances the richness of the cream.
Bring the sauce to a gentle simmer, then reduce heat to medium-low. Let it bubble gently until it coats the back of a spoon like thick cream — it should pour smoothly but cling to your stirring spoon. Taste and adjust seasoning with salt and pepper.
⏱ 3 min
Slice the rested chicken into strips and add them back to the pan along with any accumulated juices. Simmer just until the chicken is heated through and fully cooked.
⏱ 1 min
Serve immediately over the cooked pasta, spooning extra sauce over each portion. Finish with a sprinkle of fresh parsley if you're using it — the bright color and fresh flavor make a nice contrast to the rich sauce.