If you read through slow-cooker recipes, you'll notice a majority of them call for greasing the insert with nonstick cooking spray before adding the ingredients to it. But is it really necessary?
If it's something like soup or stew, there's enough liquid in the slow cooker that the ingredients won't stick to it. But for something like mashed potatoes or pasta, which are starchy and not exactly brothy, the chances for the dish sticking to the bottom is a lot more likely.
A quick mist of cooking spray can prevent a mess from occurring, which is the easy answer as to why so many recipes call for it. But if its purpose is to grease the insert and to turn it into a nonstick surface, there's no reason you can't turn to something else that serves the same purpose if you'd rather not use spray.
Instead, try coating the insert with a thin layer of softened butter, olive oil, coconut oil, or a vegetable oil like canola or grapeseed. Then proceed with the recipe and rest assured that the food won't stick.
Read More: The Science Behind Nonstick Cooking Spray