Step 1: In a large, heavy-bottomed skillet or saucepan, melt the unsalted butter over medium heat. Be careful not to burn it – just let it melt until it’s fragrant and bubbly.
Step 2: Add the minced garlic to the melted butter. Sauté for about 1 minute, stirring constantly, until it’s fragrant but not browned. Browning the garlic can make it bitter.
Step 3: Pour in the heavy cream. Bring the cream to a gentle simmer, stirring occasionally. Do not let it come to a rolling boil; a gentle simmer is all you need.
Step 4: Reduce the heat to low. Gradually add the freshly grated Parmigiano-Reggiano cheese, a handful at a time, stirring continuously with a whisk or spatula until each addition is fully melted and incorporated before adding more. This slow addition is key to a smooth, lump-free sauce.
Step 5: Continue to cook on low heat, stirring frequently, for 3-5 minutes, or until the sauce has thickened to your desired consistency. Taste and season with salt and freshly ground black pepper. Adjust seasonings as needed.
Step 6: If serving with pasta, drain your pasta, reserving about a cup of the starchy pasta water. Add the cooked pasta directly to the skillet with the Alfredo sauce. Toss gently to coat thoroughly. Serve immediately, garnished with extra Parmesan and fresh parsley, if desired.