Makes 2 sandwiches

To achieve their immense size, portobello mushrooms have a long growing cycle. In the process, some of the mushrooms' moisture evaporates. This concentrates and enriches the flavor and creates a dense, meaty texture, making portobellos ideal for grilling. This is the perfect choice for vegetarians, yet be prepared because others will want to try the giant grilled mushrooms.

For the Sun-Dried Tomato-Chevre Spread

2 tablespoons minced oil-packed, sun-dried tomatoes

2 tablespoons (about 1 ounce) chevre cheese

1 tablespoon red wine vinegar

1 tablespoon extra-virgin olive oil

1 clove garlic, minced

Pinch of sugar

Pinch of red pepper flakes, or to taste

Dash of salt, or to taste

For the sandwich filling

2 large portobello mushroom caps

Two ¼-inch-thick red onion slices

Olive oil, as needed

Dash of freshly ground pepper

Dash of salt

2 tablespoons freshly grated Parmesan cheese

8 medium-size arugula leaves

For the bread

2 crusty French onion rolls, halved horizontally

Prepare the grill.

Process all of the spread ingredients in a food processor until the mixture is nearly smooth. Taste and adjust the seasoning.

To prepare the sandwich filling, brush the rounded tops of the mushrooms and the onion slices with olive oil. Arrange them, oiled sides down, on a grill rack about 4 to 5 inches from medium-hot coals. (Or cook the vegetables on a stovetop grill pan.) Cook for about 5 minutes; brush the other sides with additional oil, then turn. Cook about 5 more minutes, or until tender and lightly browned. Transfer to a plate and sprinkle lightly with pepper and salt. Cover to keep warm.

To assemble each sandwich, spread half of the sun-dried tomato mixture on the cut sides of the roll. Sprinkle the bottom half of the roll with cheese, then add the following layers: arugula leaves, onion slices, and mushroom. Close the sandwich; fasten with long sandwich picks. Slice in half and serve warm.

Advance preparation

The spread will keep for up to 5 days in a covered container in the refrigerator. Grill the vegetables and assemble the sandwiches just before serving.