In a large skillet, heat the olive oil over medium-high heat. When the oil shimmers, sear the pork chops for 2–3 minutes per side, just until they develop a golden crust. They do not need to be cooked through at this stage. Transfer the seared chops to the prepared baking dish in a single layer.
Reduce the skillet heat to medium. If the pan looks very dry, add a teaspoon more oil. Add the minced garlic and sauté for about 30 seconds, just until fragrant, scraping up any browned bits from the pork.
Pour in the heavy cream and chicken broth, stirring to combine with the garlic and pan drippings. Whisk in the ranch seasoning mix and Dijon mustard, if using. Let the mixture come to a gentle simmer and cook for 2–3 minutes, stirring frequently, until slightly thickened.
Remove the skillet from the heat and stir in the grated Parmesan cheese until it melts and the sauce is smooth. Taste the sauce and adjust seasoning with a little more salt or pepper if needed, keeping in mind the ranch mix and Parmesan are already salty.
Pour the warm creamy ranch sauce evenly over the pork chops in the baking dish. Sprinkle the shredded mozzarella cheese over the top.
Transfer the dish to the preheated oven and bake for 18–22 minutes, or until the pork reaches an internal temperature of 145°F (63°C) in the thickest part and the sauce is bubbling around the edges.
If you’d like a more browned, bubbly top, switch the oven to broil for 1–3 minutes at the end of baking, watching closely so the cheese doesn’t burn.
Remove the dish from the oven and let the pork rest for about 5 minutes. Sprinkle with chopped fresh parsley or chives before serving. Spoon the creamy ranch sauce over each chop when plating.
