Trim excess fat from the pork chops if using bone-in chops, then arrange the four chops in an even layer in the slow cooker.

Whisk the condensed golden mushroom soup, dry onion soup mix, and water together in a bowl until mostly smooth. Stir in the optional black pepper and garlic powder if desired.

Pour the gravy mixture over the pork chops, turning the chops once so both sides are coated. Add the optional sliced onion and mushrooms around the meat.

Cover and cook on LOW for 5–6 hours or on HIGH for approximately 2 1/2–3 hours. Use the shorter cooking time for lean, boneless chops and check the center with an instant-read thermometer.

When the pork reaches at least 145°F in the center, transfer the chops to a serving platter and let them rest for 3 minutes. For a softer, more braised texture, bone-in or thicker chops may be cooked until very tender.

Stir the liquid in the slow cooker until smooth, then spoon the golden gravy over the rested pork chops. Stir 1–2 tablespoons of sour cream into the finished gravy only if you want a creamy variation.