In a small bowl, whisk together flour, onion powder, garlic powder, garlic salt and pepper.
Add milk and whisk until combined, set aside.
In a 4-quart pan over medium heat, boil water.
Add chicken bouillon and whisk until dissolved.
Add milk/dry ingredient mixture to boiling water/bouillon.
Cook over medium heat, stirring constantly, until thick (about 3 minutes).
Remove from heat and set aside.