My stand-by for a casual and satisfying Sunday night dinner, these open-faced sandwiches are a homey classic. Simply garnish the plates with bunches of juicy red grapes or other fresh fruit, and be sure to set the table with forks and knives for easy eating.

Zesty Cheese Sauce

2 tablespoons butter

2 tablespoons all-purpose flour

1 cup milk

1 cup (4 ounces) finely shredded cheddar cheese

½ teaspoon dry mustard

Salt to taste

1/8 teaspoon cayenne, or to taste

Bread
4 slices of whole-wheat bread or 4 whole-wheat English muffins, halved

Mustard for spreading

Filling

12 asparagus spears (16 or 20 if the asparagus is very thin)

1 tablespoon butter

1 tablespoon olive oil

3 cups sliced cremini mushrooms (see Tip)

Four ½-inch-thick tomato slices (at room temperature)

Dash of paprika, preferably Hungarian

Preheat the oven to 350° F. Lightly coat an 8-by -10-inch baking pan with cooking spray.

To make the sauce: Melt the butter in a medium nonstick saucepan over medium heat. Add the flour and stir constantly until the mixture is smooth and bubbly. Gradually add the milk, whisking constantly until the sauce is smooth and thickened, about 3 minutes. Reduce the heat to low; add the remaining sauce ingredients. Stir constantly until the cheese is melted. (The sauce will be quite thick.) Remove from the heat. Taste and adjust the seasoning. Cover and set aside.

Arrange the bread or English muffin halves in a single layer (rough sides up for the English muffins) in the baking pan. Toast in the oven for about 2 minutes, or until the top surfaces are lightly browned. Lightly spread each with mustard.

To make the filling: Steam the asparagus over boiling water in a covered pot for about 4 minutes, or until crisp-tender. (Or, put the asparagus spears in a medium microwave-proof dish; add about ¼ cup water. Cover tightly and microwave on high for about 3 to 4 minutes, or until crisp-tender.) Remember that the asparagus will cook again while the sandwiches are baking. Drain well.

Melt the butter with the oil in a medium nonstick skillet over medium-high heat; add the mushrooms. Cook, stirring occasionally, until tender, about 5 minutes.

Top each bread slice or muffin half with a tomato slice. Add a layer of mushrooms and asparagus spears to each. Pour the cheese sauce over the sandwiches; sprinkle with paprika. Bake the sandwiches in oven for about 8 minutes, or until the cheese sauce is bubbly.