Prep the chicken: Pat the thighs dry.
Season both sides with salt, pepper, paprika, and garlic powder. Dry skin means better browning.
Brown the chicken: Heat olive oil in a large skillet over medium-high. Place thighs skin-side down and cook without moving until deeply golden, about 6–8 minutes.
Flip and sear the other side for 3–4 minutes. Transfer to a plate. The chicken won’t be fully cooked yet.
Reduce heat and build the aromatics: Lower heat to medium.
Add butter. Stir in shallot and a pinch of salt; cook 1–2 minutes until softened. Add garlic and cook 30–60 seconds until fragrant, not browned.
Make a quick roux: Sprinkle in flour and stir for 30 seconds to coat.
This helps the sauce thicken smoothly. If using cornstarch, skip this step and add a slurry later.
Deglaze and simmer: Pour in chicken stock, scraping up the brown bits. Simmer 2–3 minutes to slightly reduce.
If using cornstarch, whisk 1 teaspoon cornstarch with 1 tablespoon cold water, then stir it into the simmering stock now.
Add cream and seasonings: Stir in the cream, Dijon, thyme, and red pepper flakes if using. Bring to a gentle simmer. Taste and adjust salt and pepper.
Return the chicken: Nestle thighs into the sauce, skin-side up.
Reduce heat to medium-low and simmer 8–12 minutes, or until the chicken reaches 165°F (74°C) at the thickest part. The sauce should thicken enough to coat a spoon.
Finish with brightness: Stir in a squeeze of lemon juice to lift the richness. If the sauce seems too thick, add a splash of stock.
If it’s thin, simmer a bit longer.
Garnish and serve: Sprinkle with parsley or chives. Add a light shower of Parmesan if you like. Serve over pasta, mashed potatoes, rice, or alongside roasted vegetables and crusty bread.