1.  Season the tenderloin(s) with salt and pepper. Melt some bacon fat or oil in an uncoated pan over high heat. Brown the tenderloin(s) on all sides. While it is browning, dice all vegetables. Make the potato and carrot uniform bite-sized, onions in large pieces.   2. Transfer browned pork to crock pot and deglaze pan with a cup of water or stock. Pour water and all drippings into crock pot.   3. Tuck onion and garlic around the meat, then add potatoes and carrots. Season with salt and pepper. Add enough water to almost cover the vegetables. Cover and turn to low for 8-12 hours, or high for 4-6 hours. (New crock pots run much hotter than older ones. Expect that your time *will* vary widely. You'll need to practice with yours to get used to it.)   4. DO NOT stir while it is cooking. The meat and vegetables will both get so soft they will fall apart. It is done when the internal temperature of the meat reaches 150°.   5.  For gravy, transfer remaining liquid to a pan. Mix ¼ cup flour with ¼ cup cold water. Add to liquid and bring to a boil. Stir constantly while it boils for 2 minutes. Check seasoning, add salt, pepper and marjoram as needed.