Ham and Cheese Casserole

Ingredients

• 12 oz short pasta such as rotini or shells
• 3 cups diced cooked ham
• 3 tbsp unsalted butter, divided
• 1 small yellow onion, finely diced
• 3 tbsp all-purpose flour
• 2 1/2 cups whole milk
• 1 tsp Dijon mustard
• 2 cups sharp cheddar, freshly shredded
• 1 cup Gruyere or Monterey Jack, shredded
• 1/2 tsp black pepper
• 1/2 cup panko breadcrumbs
• 2 tbsp grated Parmesan

Instructions

Follow each step in order. The directions below are written so a beginner can understand what to do, what to look for, and when to move on to the next step.

1. Step 1.Heat the oven to 375°F, lightly grease a 9-by-13-inch baking dish, and bring a large pot of well-salted water to a boil.
2. Step 2.Cook the pasta for about 2 minutes less than the package's al dente time, then drain well so it does not become overly soft in the oven.
3. Step 3.Melt two tablespoons of butter in a saucepan over medium heat, add the onion, and cook for 4 to 5 minutes until softened.
4. Step 4.Sprinkle in the flour and stir constantly for 1 minute, then slowly whisk in the milk until the mixture is smooth with no pockets of dry flour.
5. Step 5.Simmer gently for 3 to 5 minutes until the sauce thickens, then stir in Dijon, black pepper, cheddar, and Gruyere until melted and smooth.
6. Step 6.Fold the drained pasta and diced ham into the cheese sauce, tasting before adding any extra salt because both ham and cheese are naturally salty.
7. Step 7.Transfer the mixture to the prepared baking dish and spread it into an even layer without pressing the pasta down tightly.
8. Step 8.Melt the remaining tablespoon of butter and combine it with panko and Parmesan, then scatter the crumbs evenly over the casserole.
9. Step 9.Bake uncovered for 25 to 30 minutes until the edges bubble and the breadcrumb topping is golden brown.
10. Step 10.Rest for 5 to 10 minutes before serving so the sauce settles slightly and each portion can be spooned out cleanly.