In a medium saucepan over medium heat, melt 4 tablespoons of butter until it starts to bubble, about 1-2 minutes. Whisk in ¼ cup of all-purpose flour, stirring constantly for another 1-2 minutes until it forms a golden paste.

Slowly pour in 2 cups of whole milk while continuing to whisk the mixture. Keep stirring until the sauce begins to thicken and bubble gently, about 3-5 minutes.

Remove the saucepan from heat and stir in 1 cup of shredded cheddar cheese and 1 cup of shredded Monterey Jack cheese until melted.

If the cheese sauce is thicker than you’d like, return it to low heat and add more milk, a splash at a time, until you reach your desired consistency.

Add salt and pepper to taste, stirring well to combine.

Transfer cheese sauce to a serving bowl and garnish with fresh herbs or toppings. Serve warm with fries, nachos, or veggies.