Portobello Parmesan Sandwich with Rosemary Mayonnaise
This will delight vegetarians—and carnivores, too. The warm, meaty mushrooms are so satisfying, especially when topped with pickled chiles, arugula, and Parmesan shavings. Fragrant fresh rosemary, which too often overpowers, adds a subtle depth of flavor to homemade mayonnaise, which is key here.
Recipe information
Yield
Serves 4
Ingredients
Preparation
Step 1
Set the oven rack 6 inches from the broiler heat source. Preheat the broiler to high.
Step 2
Process the lemon juice, 1 tablespoon water, and the rosemary in a food processor until the rosemary is finely chopped. Strain through a fine-mesh sieve, pressing on the solids to extract as much liquid as possible, and return the liquid to the processor; discard the solids.
Step 3
Add the egg yolk and 3/4 teaspoon salt and process until smooth. With the machine running, add the oils in a steady stream and process until emulsified.
Step 4
Arrange the mushrooms in a single layer on a rimmed baking sheet. Season both sides liberally with salt and pepper. Drizzle generously with olive oil, turning to coat. Turn the mushrooms gill side up and broil for 8 minutes, then flip and broil until tender, about 3 minutes longer. Cut each mushroom into 4 slices at an angle, keeping each cap together.
Step 5
Toast the rolls and spread the rosemary mayonnaise on both cut sides of each roll. Arrange a mushroom, gill side up, on the bottom of each roll and top with chiles, then arugula. Use a vegetable peeler to shave the cheese directly onto the arugula. Cover with the roll tops, cut each sandwich in half, and serve immediately.
