If you entertain with any frequency at home, there's always a need for simple appetizer recipes that can be made on the fly, and that can keep your wine-swilling guests occupied and grazing while you tend to the rest of dinner.
This is one of those recipes. Meaty crimini mushrooms are tossed in a simple dressing of red wine vinegar, dijon mustard, olive oil, minced garlic, and chopped rosemary, then placed into a hot oven until tender. As they roast, the spongy mushrooms not only absorb the sharp and herbaceous flavors of the dressing, but their own meaty mushroom flavor intensifies as well.
After removing the mushrooms from the oven, they can be served warm or at room temperature. But if your guests have enough wine in them, they might not want to wait that long. In that case, just pass out the forks and let your guests dig in.