Preheat Oven: Preheat your oven to 375°F (190°C).
Prepare the Chicken and Potatoes: In a large bowl, combine the chicken and potatoes. Drizzle with 1 tablespoon of olive oil, toss to coat evenly. Season generously with salt, pepper, and the Italian seasoning blend (or Herbs de Provence).
Sear the Chicken and Potatoes: In a large skillet, melt the butter over medium heat. Add 1 tablespoon of olive oil and stir. Place the chicken on one half of the pan and the potatoes on the other half. Cook undisturbed for 3-4 minutes, flip the chicken, and cook for another 3-4 minutes until both sides are browned. Transfer the chicken and potatoes to a plate and cover to keep warm.
Prepare the Dijon Cream Sauce: In the same skillet, melt the butter over medium heat. Stir in the minced garlic and cook for 1 minute until fragrant. Add the chicken broth and Dijon mustard, whisking to combine. Gradually whisk in the heavy cream, salt, and cracked black pepper.
Combine and Bake: Return the chicken and potatoes to the skillet, tossing them in the sauce to coat well. Transfer the skillet to the preheated oven and bake for 15-20 minutes until the chicken is cooked through and the potatoes are fork-tender.
Serve: Spoon the Dijon cream sauce from the pan over the chicken and potatoes. Garnish with freshly cracked black pepper and fresh herbs if desired, and serve immediately.