Pat the pork chops dry with paper towels. Season both sides with garlic powder and black pepper, using little or no additional salt because the condensed soup and onion soup mix already contain plenty of salt.

For extra flavor, warm the cooking oil in a skillet over medium-high heat and brown the pork chops for 2 to 3 minutes per side. This step is optional, so it may be skipped when you need the quickest preparation.

Whisk together the cream of mushroom soup, chicken broth or water, and dry onion soup mix until the sauce is smooth and evenly combined.

Arrange the pork chops in the slow cooker and pour the creamy onion sauce over the top, making sure the chops are coated as evenly as possible.

Cover and cook on LOW for 5 to 6 hours for boneless chops or 6 to 7 hours for bone-in chops. You can cook on HIGH for about 3 to 4 hours, but check the meat early because slow-cooker temperatures and chop thickness vary.

If using sour cream, stir it into the sauce during the final 10 to 15 minutes of cooking. Check the thickest part of the pork with an instant-read thermometer and remove it when it reaches 145°F, then let it rest for at least 3 minutes.