CHEESY SHELLS AND GREENS

Steps:

• Cook the pasta according to the package directions.
• Meanwhile, melt the butter in a large pot over medium heat. Add the flour and cook, stirring, for 2 minutes; whisk in the milk. Cook, stirring occasionally, until slightly thickened, 5 minutes.
• Whisk in the mustard, nutmeg, cayenne (if using), 1 cup Cheddar, 1/2 tsp salt and 1/4 tsp pepper. Add the pasta and spinach and toss to combine.
• Heat broiler. Transfer the mixture to a 1 1/2-qt broiler-proof baking dish or four 12-oz ramekins. Sprinkle with the remaining 1/2 cup Cheddar and broil until golden brown, 3 to 4 minutes.