Step 1: Place a large skillet or saucepan over medium-low heat and add the butter. Allow it to melt completely until it begins to bubble slightly.
Step 2: Pour the heavy whipping cream into the skillet with the melted butter. Whisk gently to combine the two ingredients.
Step 3: Let the mixture simmer for about 3-5 minutes, whisking frequently. You want the cream to reduce slightly and become fragrant, but do not let it reach a full, aggressive boil.
Step 4: Reduce the heat to low. Add the garlic powder and a pinch of salt and pepper.
Step 5: Gradually add the freshly grated Parmesan cheese one handful at a time. Whisk continuously until the cheese is fully melted and the sauce is smooth and glossy.
Step 6: Remove from heat immediately. The sauce will continue to thicken as it sits for a minute. Toss with your favorite cooked pasta and serve warm.