In a medium sauce pan, melt butter over medium heat. Stir in garlic powder. Stir in milk (or water). Remove from heat and allow to cool for 2-3 minutes. Gradually whisk in greek yogurt.
Add parmesan cheese to sauce and stir until melted. (If the cheese doesn’t melt completely because the sauce is too cool, return to stove on low for a couple of minutes) Add salt and pepper to taste and toss with your favorite cooked pasta noodles.