If you cannot find colby cheese, longhorn will work just as well. This recipe was published in our cookbook Best American Side Dishes.
2 slices white sandwich bread , torn into quarters
1 tablespoon unsalted butter , melted
2 pounds broccoli (about 1 large bunch), florets trimmed to 1-inch pieces, stalks peeled and chopped medium ( see illustrations below)
3 tablespoons unsalted butter
1 medium garlic clove , minced or pressed through a garlic press (about 1 teaspoon)
1/2 teaspoon dry mustard
Pinch cayenne pepper
3 tablespoons unbleached all-purpose flour
1 1/2 cups whole milk
1 cup low-sodium chicken broth
8 ounces Colby cheese , shredded (about 1 1/3 cups)
4 ounces sharp cheddar cheese , shredded (about 1 1/3 cups) (Note from JB - obvious error in recipe, 8 oz of shredded colby and 4 oz of shredded cheddar can't both = 1-1/3 cups)
Ground black pepper
1. For the topping: Process the bread and butter in a food processor until coarsely ground, about six 1-second pulses; set aside.
2. For the filling: Adjust an oven rack to the middle position and heat the oven to 400 degrees. Bring 4 quarts of water to a boil in a large pot. Add 1 tablespoon salt and the broccoli to the boiling water; cover and cook until bright green and crisp-tender, about 3 minutes. Drain the broccoli and leave it in the colander; set aside.
3. Meanwhile, melt the butter in a medium saucepan over medium heat. Stir in the garlic, mustard, and cayenne; cook until fragrant, about 30 seconds. Add the flour and cook, stirring constantly, until the flour turns golden, about 1 minute. Slowly whisk in the broth and milk; bring to a simmer and cook, whisking often, until large bubbles erupt at the surface and the mixture is slightly thickened, about 5 minutes. Off the heat, whisk in the colby and cheddar. Season to taste with salt and pepper.
Spread the broccoli in a 13 by 9-inch baking dish (or shallow casserole dish of
similar size). Whisk the cheese sauce again briefly and pour over the broccoli.
Sprinkle with the bread-crumb topping. Bake until golden brown and bubbling
around the edges, about 15 minutes. Cool for 5 minutes before serving.