Balsamic-Glazed Portobello Burgers
Topped with sautéed onions and blue cheese, these balsamic-glazed portobello burgers are a deliciously satisfying alternative to ground beef.
large sweet onions
Salt and freshly ground black pepper
crumbled blue cheese
soft sandwich rolls
Brush any dirt from the mushroom caps, remove the stems and reserve them for another use.
Place the balsamic vinegar in a small saucepan and bring to a simmer over medium-high heat.
Immediately reduce the heat to medium and continue cooking, stirring occasionally, until the vinegar is reduced by about half, 5 to 6 minutes.
Remove from the heat and set aside to cool for 10 minutes.
Use about half of the reduction to brush the tops of the mushrooms, then set them aside while you sauté the onions.
Separate the onions into rounds. Heat the oil in a large skillet over medium heat. Add the onions, season with salt, pepper and a pinch of sugar.
Sauté until the onions are soft, translucent and beginning to brown, 5 to 7 minutes.
Preheat a gas or charcoal grill to a medium temperature (about 400°F).
Oil the grates and add the mushrooms, gill side up.
Grill for 3 minutes, then turn them over, brush with the rest of the balsamic reduction and grill until tender, about 3 minutes longer.
Top each mushroom with a portion of blue cheese and cook just until the cheese begins to melt, 1 minute more.
To serve, place a portion of onions on the bottom of each bun, add a cheese-topped portobello and serve immediately.