Make your own white sauce. Its simple to do, uses simple ingredients, is economical and great on pasta, potatoes, rice, chicken. Use on any food you would like a white sauce.
NOTE: you should be constantly stirring this for the duration (after adding flour) so it has a smooth consistency.
Melt butter in a small pan over medium to low heat and add the flour. Stir butter through flour until evenly dissolved, we don't want to have any lumps.
Slowly add milk, continuously stirring,
Add in the milk bit by bit, without burning, and once, milk is added, keep on stirring until mixture thickens. This process should take roughly 2-3 minutes.
When you notice it thickening, continue stirring, and slowly add cheese, bit by bit. Add mustard, and salt and pepper.
If you find the sauce is too thick, add a milk a small amount at a time until you reach the consistency you would like.
Great on pasta, potatoes, rice, chicken, any where you need a white sauce.