Dump a whole pork tenderloin in the slow cooker with 3 simple ingredients and your husband will swear you spent all day cooking.
Pour the soup and onion mixture evenly over the pork tenderloin, making sure the top is well coated. Some of the mixture will run down and pool around the meat, which will become the base of your savory gravy.
Cover the slow cooker with the lid and cook on LOW for 4 to 5 hours, or on HIGH for 2 to 3 hours, until the pork tenderloin is very tender and reaches an internal temperature of at least 145°F (63°C) when checked with an instant-read thermometer at the thickest part.
Once done, transfer the pork tenderloin to a cutting board and let it rest for about 5 minutes. While it rests, give the sauce in the slow cooker a quick stir to combine any separated juices into a smooth, savory gravy.
Slice the pork tenderloin into 1/2-inch thick medallions. Arrange the slices on a serving platter or individual plates and spoon the warm onion-mushroom gravy over the top. Serve immediately with your favorite sides.
Variations & Tips
For a slightly richer flavor, you can substitute beef broth for the water (keep the same amount) or add 1 tablespoon of Worcestershire sauce to the soup mixture—this will deepen the savory notes without adding any extra steps. If you prefer a lighter sauce, use a condensed cream of celery soup instead of cream of mushroom.
To add a touch of sweetness, scatter 1 small sliced onion or 1/2 cup sliced carrots around the pork before pouring on the soup mixture; they’ll soften into the sauce as it cooks. If your tenderloin is on the larger side (closer to 2 pounds), plan on the longer end of the cooking time and confirm doneness with a thermometer.
Food safety tips: Always keep raw pork refrigerated until you’re ready to cook, and avoid letting it sit at room temperature for more than 30 minutes. Use a dedicated cutting board and knife for raw meat, and wash them (and your hands) thoroughly with hot, soapy water before handling other ingredients. The USDA recommends cooking pork to a minimum internal temperature of 145°F (63°C) followed by a short rest; in a slow cooker, the meat will often go higher, which is fine for tenderness. Refrigerate leftovers within 2 hours in shallow containers and use within 3 to 4 days, reheating until hot and steaming before serving.
