Gather and prepare all ingredients.
Pour the milk into a shallow bowl.
Place the flour into another shallow bowl.
Dip each chicken breast into the milk.
Coat thoroughly with flour.
Heat the vegetable oil in a large skillet over medium-high heat.
Cook the chicken for about 3 minutes per side until lightly golden.
Remove the chicken and place it on a plate.
Carefully discard excess oil from the skillet.
Melt the butter in the same skillet.
Add the sliced mushrooms and sauté for about 2 minutes until softened.
Stir in the chicken broth mixture.
Add the prepared chicken gravy, half-and-half, and Dijon mustard.
Season with salt and pepper.
Simmer the sauce for about 2 minutes until slightly thickened.
Return the chicken to the skillet.
Spoon the sauce over the chicken.
Continue cooking for about 5 minutes, or until the chicken reaches an internal temperature of 165°F (74°C).
Serve the Chicken Mushroom Dijon Recipe immediately with your favorite side dishes.