1-First, microwave 1 cup milk for 45 seconds to temper it and set it aside for later.

2-Next, melt 4 tablespoons butter in a saucepan over medium heat until it’s fully melted and foamy, which takes about 3 minutes.

3-Gradually whisk in ½ cup plus 2 tablespoons flour, stirring continuously for 3-5 minutes until the mixture looks like wet sand, then remove from heat.

4-Add one-third of the 2 cups chicken broth and whisk well; repeat this with another third of the broth.

5-Now, mix in the remaining chicken broth, 1 chicken bouillon cube or 1 teaspoon bouillon paste if you’re using it, the tempered milk, ⅓ teaspoon celery salt, ⅓ teaspoon onion powder, ⅓ teaspoon garlic powder, ⅓ teaspoon salt, and ⅓ teaspoon black pepper while whisking continuously.

6-Return the pan to the heat and bring it almost to a boil, whisking until it thickens, then remove it immediately from the heat.

7-Let the soup cool a bit; it will thicken more as it sits, and for extra smoothness, strain it through a fine mesh sieve.