Trim chicken and sprinkle both sides with salt and pepper.
Add oil to a large oven safe skillet over medium heat. When oil is hot, place chicken in skillet. Cook for 3-4 minutes or until golden brown and it removes easily from the pan (it shouldn’t stick). Flip each piece over and cook for another 3-4 minutes.
Place the pan in the oven and bake for 10 minutes or until the internal temperature of the chicken breasts reaches 165ºF when checked with an instant-read thermometer in the thickest portion of the meat.
Remove chicken from the pan and place it on a plate. Cover with foil.
Return pan to burner over medium heat.
Add shallots and cook for 3-4 minutes or until softened. Add rosemary and garlic and cook, stirring constantly, for 1 minute or until garlic is fragrant. Stir in flour and cook for 1 minute, stirring constantly.
Whisk or stir in wine while scraping all the brown bits off the bottom of the pan. Continue to cook for 1-2 minutes or until slightly reduced.
Add mustard while whisking, and then add chicken broth while whisking.
Cook for 5-6 minutes or until thickened slightly. Whisk in cream and cook for 5 minutes, stirring frequently, or until thickened. Return chicken to pan to coat in sauce (or drizzle sauce over chicken) and serve immediately, garnished with fresh parsley or chives if desired.
If you’d like to lighten this up a little or make it dairy free, leave out the cream.
If you want to make this without wine, substitute an extra 1/2 cup of chicken broth instead.
Love or hate garlic? Feel free to add more or leave it out.
If you don’t have shallots, you could also use finely diced onion.
Prefer chicken thighs? They would work with this recipe, too. Keep in mind that you may have to adjust cooking time.
Gluten-free? Instead of thickening with flour, try using a gluten-free flour or cornstarch.