Heat a heavy saucepan on medium heat. Add butter and melt it, but don't let it brown.
3 tablespoons butter
Add flour and whisk for 1 minute until thickened.
3 tablespoons white all purpose flour
Add chicken broth, garlic powder, onion powder, and salt and whisk until smooth.
2 cups chicken broth, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1/2 teaspoon salt
Let it come to a light boil and whisk it as it thickens. (About 5 minutes).
Take off heat and let cool for 5 minutes.
Add sour cream and stir it in.
1 cup sour cream
Put the pan back on low heat, add cheese, and stir until melted.
1/4 cup shredded cheddar cheese
This is optional: add 1/2 cup or less of chicken broth to thin the sour cream sauce to your liking.
Ladle on enchiladas or dish of your choice.
Enjoy