Juicy roasted portobello mushrooms make a luxurious sandwich for the vegetarians at your picnic table. Drape a slice of your favorite cheese over the top — sharp Vermont cheddar or mild Muenster both work well.
6 large portobello mushrooms, stems removed
Olive oil, for brushing
Kosher or sea salt and freshly ground black pepper, to taste
1/2 cup mayonnaise
1 tablespoon fresh lemon juice
1 tablespoon chopped fresh dill
12 slices whole wheat or seven-grain bread (6 slices if serving open-faced)
1 English cucumber, peeled and sliced
1 4-ounce package alfalfa sprouts
1 ripe avocado, peeled, pitted, and sliced
6 slices Muenster or Vermont cheddar cheese
Heat oven to 400°. Brush mushrooms with olive oil and sprinkle with salt and pepper. Place on a baking sheet, gill side down, and cook about 8 minutes on each side (these are also great grilled). Remove from oven and cut into 1/2-inch strips. If possible, use while still warm.
In a small bowl, combine mayonnaise, lemon juice, and dill. Spread a thin layer of the mayonnaise on one side of bread slices. Divide ingredients among 6 slices of bread, layering them in this order: cucumber, sprouts, avocado, mushrooms, and cheese (if the mushrooms are warm, the cheese will melt a little and hold things together). Top with remaining slices of bread or serve open-faced.