Prepare Pork Chops: Choose bone-in pork chops at least 1 inch thick, preferably 2 inches. Season both sides generously with rosemary salt and finely ground black pepper. Use more salt for thicker chops.
Preheat Pan and Sear Fat Cap: Preheat a stainless steel pan over medium-high heat for 3-4 minutes. Add avocado oil. Place pork chops fat side down using tongs, searing the fat cap until golden brown and rendered, about 2 minutes. Roll chops to sear edges if needed.
Sear Pork Chops: Lay pork chops flat in the pan and press lightly for good contact. Sear for about 4 minutes on one side until well browned, then flip and sear the other side for 1 minute.
Add Aromatics and Butter: Add halved shallot and smashed garlic cloves (with peel) to the pan. Reduce heat to low and add 2 tablespoons unsalted butter. Allow butter to foam before basting the pork chops, focusing on the thickest part near the bone to ensure even cooking.
Add Thyme and Finish Basting: In the last 30 seconds of cooking, add fresh thyme sprigs to the pan. Continue basting with the foaming butter for about 1 minute.
Rest Pork Chops: Remove pork chops from the pan and let rest for about half the cooking time (approximately 4-5 minutes) to allow juices to redistribute. Aim for an internal temperature of about 130°F (54°C) for a slightly pink, tender chop.
Make Balsamic Orange Glaze: In the same pan with the fond, add 1 cup orange juice and whisk to scrape up browned bits. Reduce by about 50%. Add 1/3 cup balsamic vinegar and reduce again by 50-60% until thickened. Turn heat to low and whisk in cold unsalted butter cubes gradually in 4-5 stages until sauce is glossy and thickened. Season with rosemary salt and black pepper to taste.
Serve: Slice pork chops off the bone and serve with the balsamic orange glaze spooned over. Optionally, serve with extra sauce on the side.