Hi Ruquaiya, It is easy but tricky. Take 1-1-1 That is 1tb.spoon of butter, 1tb.sp. of maida and 1 cup milk at room temperature. Heat the butter on low flame, add maida and roast till the row smell goes,it should not change its colour. Now remove it from flame and add 1tb.sp. milk and keep stirring constantly so that there are no lumps. Repeat this till the milk is over. Now put it on the flame and keep stirring constantly till the sauce becomes thick. Now add salt and pepper pwd as per your taste and grated cheese. You can add sugar if you like it little sweet.
If you add milk at a time it will become lumpy. You can adjust the consistency of the sauce as per recipe.
7 year, 7 months ago