Bring a large pot of salted water to a boil. Add the gluten-free pasta and cook according to package instructions until al dente, which typically takes around 8-10 minutes. Reserve about 1 cup of pasta water before draining the pasta.
While the pasta is cooking, melt 4 tablespoons of unsalted butter in a skillet over medium heat. Add the minced garlic and sauté for about 1-2 minutes until fragrant, being careful not to burn it.
Pour in the heavy cream and stir. Let it simmer for 2-3 minutes, allowing it to thicken slightly.
Gradually stir in the grated Parmesan cheese, mixing until the cheese has melted and the sauce is creamy. If the sauce is too thick, add a splash of reserved pasta water to reach your desired consistency.
Once the pasta is cooked and drained, add it to the skillet with the garlic parmesan sauce. Toss gently to combine, ensuring the pasta is well coated. If the sauce is too thick, add reserved pasta water as needed.
Season with salt and black pepper to taste.
Serve immediately, garnished with chopped fresh parsley if desired.