Heat a pot over medium flame. Add butter and allow it to melt completely.
Add all-purpose flour and keep stirring until there are no lumps or patches of dry flour.
Let it cook for a couple of seconds until it starts bubbling and is fragrant (raw flour smell is gone).
Note: In the video, I poured the milk after this and forgot to add the seasoning first. But you should not make this mistake. Because if you add the seasonings later on then it will create lumps in the sauce and it will be difficult to mix. But if you cook the powdered spices in the butter then they won’t form lumps.
After cooking the flour, lower the flame and add salt, red chilli powder, garlic powder and onion powder. Give it a good stir and cook for a few seconds. Make sure you don’t burn the spices.
Pour milk and keep stirring until the sauce is smooth and there are no lumps. Bring it to a boil. Once it starts becoming thick, turn the flame off.
Then add grated cheese and keep stirring until the cheese has completely melted.
Sauce Tip: Want to use the sauce later on? Then pour it in a bowl or tray and cover it with wax or baking paper (directly touching the sauce). This will prevent the formation of skin over the sauce. If you don’t have wax paper, then pour a thin layer of milk or spread 1 tsp butter over the surface of the sauce. Once it cools down, cover it with a lid and refrigerate.