Pat the chicken breasts dry. If the chicken breasts are very thick, slice them horizontally into thinner cutlets or pound them to an even thickness.

Add the chicken to a bowl with 1 tablespoon olive oil, garlic powder, paprika, salt, and black pepper. Mix until the chicken is evenly coated on both sides.

Heat the remaining 1 tablespoon olive oil in a large skillet over medium-high heat.

Add the chicken breasts and cook for 6 to 8 minutes per side, or until golden brown and cooked through. The chicken should reach 165°F / 74°C in the thickest part.

Transfer the chicken to a plate and cover loosely to keep warm.

In the same skillet, melt the butter over medium heat. Add the chopped onion and cook for 2 to 3 minutes, until softened.

Add the minced garlic and cook for about 30 seconds to 1 minute, stirring often, until fragrant.

Stir in the Dijon mustard and chicken broth, scraping up any browned bits from the bottom of the skillet.

Add the Parmesan cheese and thyme. Stir well and let the sauce simmer for 2 to 3 minutes.

Pour in the heavy cream and stir until the sauce is smooth and creamy. Simmer gently for another 2 to 3 minutes, until slightly thickened. Do not boil the sauce hard.

Taste and adjust with salt and black pepper if needed.

Return the chicken to the skillet and spoon the sauce over the top. Let it simmer for 2 to 3 minutes, until the chicken is warm and coated in the mustard cream sauce.

Serve warm with extra sauce spooned over the chicken.

Notes

Use Dijon mustard, not yellow mustard, for the best flavor.

Very thick chicken breasts should be sliced into cutlets or pounded evenly so they cook faster and stay juicy.

Keep the sauce at a gentle simmer after adding the cream. Boiling it too hard can make the sauce separate.

Store leftovers in an airtight container in the refrigerator for 3 to 4 days.

Reheat gently with a splash of chicken broth, water, or cream to loosen the sauce