Ingredients
- 1 tablespoon unsalted butter
- 1⁄2 cup finely chopped yellow onion
- 1⁄4 cup unsifted all-purpose flour
- 1⁄2 teaspoon salt, or to taste
- 1⁄4 teaspoon freshly ground black pepper, or to taste
- 1½ cups milk
- 2 cups coarsely grated sharp Cheddar cheese
- 2 cups elbow macaroni, cooked according to package directions and well drained
- 2 jars (2 ounces each) diced pimientos, well drained
- 1⁄3 cup firmly packed mayonnaise or, if you prefer, mayonnaise-relish sandwich spread
- 1½ cups moderately fine soft white bread crumbs tossed with 1½ tablespoons melted unsalted butter (Topping)
How to Make It
- Preheat oven to 350°F. Spritz shallow 2-quart casserole with nonstick cooking spray and set aside.
- Melt butter in large heavy saucepan over moderate heat, add onion, and cook, stirring now and then, about 5 minutes until limp and golden.
- Whisk flour, salt, and pepper into milk and when smooth, gradually whisk into onion and cook, stirring constantly, 3 to 5 minutes until thickened. Whisk in 1½ cups grated cheese and when melted, fold in macaroni, pimientos, and mayonnaise. Taste for salt and pepper and adjust as needed.
- Scoop macaroni mixture into casserole; spreading to edge. Scatter remaining 1⁄2 cup cheese, then Topping, evenly over all.
- Slide onto middle oven shelf and bake uncovered 30 to 35 minutes until bubbling and brown.
- Serve as the main course of a simple lunch or supper. A tossed salad of crisp greens, tartly dressed, is all you need to accompany.
