Creating Decadent French Chicken with Creamy Mustard-White Wine Sauce is simple if you follow these clear steps:

1. Prepare Chicken: Season the chicken breasts with salt and pepper on both sides.
2. Heat Oil: In a large skillet, heat the olive oil over medium-high heat.
3. Brown Chicken: Add the chicken to the skillet and cook for about 5-6 minutes on each side, or until golden brown and cooked through. Remove the chicken from the skillet and set aside.
4. Sauté Onions: In the same skillet, add the chopped onion and cook for 2-3 minutes until softened. Add the minced garlic and cook for an additional minute.
5. Deglaze with Wine: Pour in the white wine, scraping the bottom of the skillet to remove any browned bits. Allow the wine to simmer for about 5 minutes until reduced by half.
6. Add Cream and Mustards: Stir in the heavy cream, Dijon mustard, whole grain mustard, and thyme. Mix well and let the sauce simmer for about 3-4 minutes until slightly thickened.
7. Return Chicken to Skillet: Place the chicken back into the skillet, spooning the sauce over the top. Cook for an additional 2-3 minutes to heat through.
8. Garnish: Remove from heat and garnish with fresh parsley before serving.

These steps will guide you effortlessly through the preparation of this delicious dish, ensuring each flavor shines through.