Chicken-Vegetable Soup with Ranch

3 tablespoons unsalted butter
1 cup diced onion
1 tablespoon minced garlic
3 tablespoons all-purpose flour
1 package powdered ranch dressing seasoning (1 oz.)
5 cups low-sodium chicken broth
1 package frozen asparagus stir-fry or frozen vegetable medley such as Birdseye (14.4 oz)  WE DOUBLED THIS
2 cups shredded rotisserie chicken breast


Melt butter in large pot over medium heat. Add onion and garlic; cook until beginning to soften, 3 minutes. Whisk in flour and ranch to coat vegetables, then whisk in broth and bring to a boil. Reduce heat and simmer soup until slightly thickened, 5 minutes. Stir in frozen vegetables and chicken; cook just to heat through, about 5 minutes. Add dill and season soup with pepper.