Add all ingredients to the bowl of a larger food processor (at least 7-cup capacity). Process until smooth and creamy. Do this in multiple batches if your food processor is smaller.
Pour out sauce into a medium saucepan set over medium-low heat. Cook for 10-15 minutes, stirring/whisking occasionally, until the sauce has thickened to your liking. You don't want the sauce to boil.
Cook the pasta (if using) while the sauce is heating. Bring a large pot of water to a boil and salt generously. Add the pasta and cook according to package directions.
Drain pasta and add it back to the pot. Pour in thickened alfredo sauce and toss to combine evenly. Serve immediately as it'll thicken as it sits/cools.
