Directions

1. Fill a large pot with lightly salted water and bring to a rolling boil over high heat. Stir in the linguine, and return to a boil. Cook, uncovered, stirring occasionally, until the pasta has cooked through, but is still firm to the bite, about 11 minutes. Drain.
2. Meanwhile, melt the 2 tablespoons butter in a large pot over medium-high heat. Stir in the onions, garlic, mushrooms, and broccoli, and cook and stir for 5 minutes. Pour in the chicken broth; cover and simmer until broccoli is just tender. Stir in the chicken, and cook until chicken is no longer pink in the center, about 5 minutes.
3. While the chicken is cooking, melt the butter in a saucepan over medium-low heat. Whisk in the flour, and stir until the mixture becomes paste-like and light golden brown, about 5 minutes. Add the butter-flour mixture to the chicken mixture, stirring constantly with a fork to prevent lumps. Pour in the milk, stirring constantly until smooth. Reduce heat to medium; simmer for 5 minutes more.
4. Stir in the Colby-Jack cheese; reduce heat to low and continue stirring until cheese is melted. Stir in the linguine. Season to taste with salt and pepper.