Classic Mac & Cheese - Epic Failure!

Okay... I don't think I have ever in my life ruined a meal like I did this meal in February.  It was a recipe that I found on Pinterest and it looked really good.  I don't know what I did wrong but it didn't work and it looked completely nasty; even Ryan (who will eat almost anything) didn't want to eat it.  That night we ate out and chucked this dinner.  I was really sad.  If anyone has any suggestions of where I might have gone wrong I would love any help. Here is the recipe that I used:

Classic Mac and Cheese

Yield: 8-10 servings

Ingredients:

For the bread crumb topping:

2 tbsp. unsalted butter

¾ cup panko bread crumbs

1 tsp. dried parsley

Salt and pepper

For the pasta:

1 lb. pasta shapes

6 tbsp. unsalted butter

2 cloves garlic, minced

1 tsp. dry mustard

¼ tsp. cayenne pepper

6 tbsp. all-purpose flour

2¼ cups low-sodium chicken broth

3½ cups milk

1 lb. colby jack cheese, shredded

8 oz. extra sharp cheddar cheese, shredded

Ground black pepper

Directions:

To make the bread crumb topping, melt the butter in a medium skillet over medium heat.  Add in the panko and cook, stirring frequently, until the bread crumbs are a light golden brown.  Remove from the heat and stir in the parsley.  Season with salt and pepper to taste.  Set aside to cool.

Preheat the oven to 400˚ F.  Bring a large pot of salted water to boil.  Add the pasta to the water and cook just until it begins to soften, about 5 minutes.  Drain the pasta and leave in the colander.

Return the pot to the heat.  Melt the butter over medium-high heat.  Stir in the garlic, dry mustard, and cayenne, cooking just until fragrant, about 30-60 seconds.  Whisk in the flour and cook, stirring constantly, until golden, about 1 minute.  Whisk in the chicken broth and milk and continue to heat, stirring frequently, until the mixture bubbles and thickens slightly, about 10 minutes.  Remove from the heat.  Stir in the cheeses, whisking until completely melted.  Season with salt and pepper to taste.  Stir the drained pasta into the cheese sauce.

Pour the pasta and cheese mixture into a lightly greased 9 x 13" baking dish.  Sprinkle with the bread crumb topping.*  Bake 30-35 minutes, until the sauce is bubbling and the bread crumbs are golden brown.  (You may want to place a baking sheet on the rack underneath the baking dish to catch any sauce that bubbles over.)  

*At this point, the dish can be wrapped tightly with foil and refrigerated for up to 2 days.  To serve, bake covered at 400˚ F until the filling is hot throughout, about 40-45 minutes.  Remove the foil and continue to bake until the breadcrumbs are crisp, 15-20 minutes more.