In a medium, heavy-bottom saucepot, melt butter over medium heat.
Once butter is melted, add pressed garlic.
Cook garlic until it’s fragrant and sprinkle flour over it. Stir until flour is all mixed with butter.
Slowly pour in heavy whipping cream while constantly stirring.
Gently stir the mixture and let it heat through.
Whisk in sour cream, Parmesan cheeses, salt, and pepper.
Lower heat to medium-low and gently stir until grated cheese melts and incorporates.
Keep cooking over medium-low heat for about 5 minutes, stirring often.
Once sauce is ready, mix it with cooked pasta. Reserve a little bit of sauce to drizzle over shrimp.