Scatter the butter pieces evenly over the top of the noodles and liquid.
Cover the slow cooker with the lid and cook on HIGH for 1 hour 30 minutes to 2 hours, or on LOW for 3 to 3 1/2 hours, until the noodles are tender but still slightly firm (al dente). Cooking times can vary based on your slow cooker, so start checking around the earliest time.
Cream mixture being poured over pasta in slow cooker
Cream mixture being poured over pasta in slow cooker
Once the noodles are tender, quickly remove the lid and add the grated Parmesan cheese. Use tongs to gently toss the pasta, sauce, and cheese together until the cheese melts and the sauce thickens and coats the noodles. If the mixture seems too thick, splash in a little extra warm chicken broth or hot water, a tablespoon at a time, until it reaches your desired creaminess.
Taste and adjust seasoning with additional salt and pepper if needed. Replace the lid and let the pasta sit on WARM for 5 to 10 minutes to allow the sauce to finish thickening and clinging to the noodles.
Serve immediately, topped with extra Parmesan cheese and freshly cracked black pepper. If the pasta sits too long and thickens, you can loosen it with a bit more warm broth or hot water and toss again before serving.
Variations & Tips
To add protein, stir in 1 to 2 cups of cooked, shredded rotisserie chicken or diced cooked ham when you add the Parmesan, then let it warm through on LOW or WARM for about 10 minutes.
Finished fettuccine being tossed with Parmesan
Finished fettuccine being tossed with Parmesan
For a little green and extra nutrition, fold in 1 to 1 1/2 cups of baby spinach or frozen peas during the last 15 minutes of cook time; they’ll soften right into the sauce. If you prefer a richer flavor, swap half of the chicken broth for whole milk, keeping an eye on the pasta so it doesn’t overcook.
For a vegetarian version, use vegetable broth instead of chicken broth and be sure your Parmesan is a vegetarian-friendly style. You can also add 1/2 to 1 teaspoon of Italian seasoning or crushed red pepper flakes with the garlic powder for extra flavor.
Slow cooker fettuccine with spinach variation
Slow cooker fettuccine with spinach variation
Food safety tips: Keep all dairy (heavy cream, butter, and Parmesan) refrigerated until you’re ready to cook, and don’t leave the finished pasta sitting at room temperature for more than 2 hours; refrigerate leftovers promptly in a shallow container.
Reheat leftovers gently on the stovetop or in the microwave with a splash of broth or milk to keep the sauce creamy and avoid overheating, which can cause the sauce to separate.
