Step 1: Pat pork chops very dry with paper towels. Season generously on both sides with salt, pepper, and garlic powder. Let sit at room temperature for 15-20 minutes.
Step 2: Heat olive oil in a large, heavy-bottomed skillet (cast iron or stainless steel recommended) over medium-high heat until shimmering and just barely smoking.
Step 3: Carefully place pork chops in the hot skillet. Do not overcrowd; cook in batches if necessary. Sear for 3-4 minutes per side until deeply golden brown and a crust forms.
Step 4: Reduce heat to medium-low. Add butter, fresh thyme sprigs, and crushed garlic cloves to the pan. Baste the pork chops continuously with the melted butter and aromatics for 3-5 more minutes, flipping occasionally, until an internal temperature of 145°F (63°C) is reached with a meat thermometer.
Step 5: Remove pork chops from the pan and transfer to a cutting board. Tent loosely with foil and let rest for at least 5-10 minutes.
Step 6: While chops are resting, add sliced mushrooms to the same skillet (add a little more butter/oil if needed). Sauté over medium-high heat until they release their moisture and turn golden brown, about 5-7 minutes.
Step 7: Stir in the minced shallots and cook for 2-3 minutes until softened and fragrant. Deglaze the pan by adding white wine (or chicken broth) and scraping up any browned bits. Simmer for 1-2 minutes.
Step 8: Pour in the chicken broth and bring to a simmer. Cook for 3-5 minutes, allowing the sauce to reduce by about half.
Step 9: Reduce heat to low. Stir in the heavy cream and Dijon mustard. Season with salt and pepper to taste. Simmer gently for 3-5 minutes, stirring occasionally, until the sauce thickens slightly.
Step 10: Slice the rested pork chops against the grain or serve whole. Spoon the creamy mushroom sauce generously over the pork chops. Garnish with fresh parsley or chives and serve immediately.