01 -
Melt the butter in a medium saucepan over medium heat. Whisk in the flour and cook, stirring constantly, for 1 to 2 minutes until the mixture is bubbly and golden.
02 -
Gradually whisk in the milk, ensuring the mixture is smooth with no lumps. Continue to cook, stirring frequently, until the sauce thickens and begins to gently bubble.
03 -
Remove the saucepan from the heat and add the grated cheddar and Monterey Jack cheeses. Stir until completely melted and the sauce is smooth. Add a splash of milk if a thinner consistency is desired.
04 -
Season with salt, pepper, and any desired optional spices. Stir well, taste, and adjust the seasoning as needed before serving.