Macaroni/ Penne and Cheese

Recipe adopted from Everyday Food:

1. Preheat oven to 375°. Cook pasta, and drain; reserve. Meanwhile, in a 5-quart heavy pot, melt butter over medium heat. Add onion; cook, stirring occasionally, until softened, 3 to 5 minutes. Whisk in flour to coat onion. In a slow steady stream, whisk in milk until there are no lumps.
2. Cook, whisking often, until mixture is thick and bubbly and coats the back of a wooden spoon, 6 to 8 minutes. Stir in cayenne, if using, and 1 cup each yellow and white cheddar cheese. Season with 1 teaspoon salt and ¼ teaspoon pepper.
3. Toss pasta with cheese mixture; fold in ham. Transfer to a 9-by-13-inch baking dish or individual dishes. Set aside.
4. In a food processor, pulse bread until large crumbs form. Toss together with remaining ¼ cup each white and yellow cheddar, and ¼ teaspoon salt. Top pasta with breadcrumb mixture. Bake until top is golden, about 30 minutes.

Penne, ham and cheese baked in the oven, pieces of bread should be added in later when it is almost finished.