Add the potatoes to a large pot and cover with water. Bring to a boil and cook the potatoes until fork tender. While the potatoes boil, make the chicken and the sauce.

Once the potatoes finish cooking, strain the water then add the potatoes back to the pot. Add the butter, heavy cream, and salt. Use an electric mixer (or potato masher) to mash the potatoes until smooth and creamy. Cover with a lid to keep warm while the chicken finishes baking.

Season both sides of the chicken breasts with salt, pepper, and garlic powder.

Melt the butter and olive oil in a large skillet over medium-high heat. Once hot, add the chicken and let cook for about 5 minutes until browned, then flip and cook another 5 minutes. Remove the chicken to a plate.

Preheat the oven to 375 degrees F. Now make the dijon cream sauce.

Reduce the heat to medium. To the same skillet, add the butter and garlic; cook until the butter is melted. Whisk in the flour and let cook for one minute.

While whisking, gradually pour in the chicken broth then the white wine. Whisk in the dijon mustard, salt, and pepper. Whisk in the heavy cream and let simmer for 1-2 minutes until slightly thickened to a gravy consistency.

Add the chicken back to the skillet with the sauce. Transfer the skillet to the oven and bake for 15-18 minutes, or until the chicken is fully cooked.

Serve the chicken and dijon cream sauce over mashed potatoes. Garnish with parsley, if desired.