1. Pat chicken breasts dry, then pound until 1-inch thick. Season with salt and pepper on both sides.
2. Add oil to a large skillet and bring it to medium high heat, adding butter once heated. Melt butter and stir it to mix with the oil.
3. Cook chicken breasts in a single, not-crowded layer, about 5-7 minutes on each side. Transfer cooked chicken to a plate, setting aside while making the sauce.
4. Reduce heat to medium and add in shallots, cooking until softened, about 4-6 minutes.
5. Add in white wine, stirring to scrape off any stuck-on bits at the bottom of the pan. Increase heat to high and simmer until reduced by half.
6. Stir in the remaining ingredients: chicken broth, heavy cream, both mustards, and thyme, cooking until lightly thickened, about 2-4 minutes.
7. Add the chicken breasts back into the pan, stirring and spooning sauce over the chicken until coated and heated through, about 1-3 minutes.
8. Serve with baked potatoes or mashed potatoes, brussels sprouts, and this pineapple casserole. Enjoy!

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