First, collect and measure all the ingredients according to the list.
Then, melt butter in a saucepan over medium heat.
Add flour and stir for 1 to 2 minutes.
After that, gradually add milk and bring a boil.
Then, add heavy cream and stir constantly.
After adding heavy cream reduce the heat to low and thicken the sauce to your desired consistency. Continuous heating is mandatory in thickening step.
Now, add garlic powder, salt, and ground black pepper to season the sauce.
Taste and adjust according to your taste.
Stir parmesan cheese to get silky and rich texture.
Serve the sauce with your favorite dish and enjoy.