Shred about a cup of cheddar cheese.
Make a white roux using about 2tbls each of butter and flour (melt the butter, whisk in the flour gradually and cook a couple of minutes whisking pretty constantly - don't let it start to brown or you'll have a blonde roux),
Whisk 1 cup of milk gradually, making sure it's completely incorporated between each new addition. Heat until it's almost at a boil.
Gradually add cheese, whisking each new portion of cheese until it's smooth and incorporated.
If it's too thick for you, add a touch more milk, conversely add a touch more cheese.
Add white pepper to taste.
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