Preheat oven to 375 degrees.
Prepare the chicken and potatoes
Combine chicken and potatoes in a large bowl. Drizzle with 1 tablespoon olive oil, toss to coat, then season generously with salt and pepper, and the Italian seasoning blend (or Herbs de Provence).
In a large skillet, melt butter over medium heat. Drizzle in 1 tablespoon olive oil and give it a good stir.
Add chicken to one half of the pan, potatoes to the other half. Cook undisturbed for 3-4 minutes, flip chicken and cook another 3-4 minutes til browned on both sides. Transfer chicken and potatoes to a plate and cover to keep warm.
Prepare the sauce
In the same skillet, melt butter over medium heat. Stir in garlic for 1 minute til fragrant.
Stir in chicken broth and dijon mustard, then whisk in heavy cream, salt and pepper.
Put it together
Return chicken and potatoes to the pan, giving them a good toss in the sauce to keep them from drying out in the oven.
Transfer to preheated oven and bake for 15-20 minutes until chicken is cooked through and potatoes are fork-tender.
Spoon dijon sauce from the pan over the chicken and potatoes, garnish with freshly cracked black pepper and fresh herbs if desired, and serve.
