Melt The Butter: In a medium saucepan, melt the butter over medium heat. Once melted, whisk in the flour until you get a smooth paste (this is your roux). Let it cook for 1 minute to eliminate the raw flour taste.

Add The Milk: Slowly pour in the warm milk, whisking constantly to avoid lumps. Keep stirring until the mixture thickens, about 3-5 minutes.

Pro Tip: If it looks lumpy, don’t panic—keep whisking! The heat will smooth it out.

Add The Cheese: Lower the heat and stir in the shredded cheese a handful at a time. Stir until melted and creamy. Add salt to taste.

Serve: Your cheese sauce is ready! Pour it over nachos, mix it into macaroni, or serve as a dip with fries.