Portobella Mushroom Burgers

4 large Portobella mushroom caps, cleaned
1/2 cup olive oil
1/4 cup balsamic vinegar
1/2 teaspoon oregano
1/2 teaspoon basil
1 clove garlic, minced
Salt and freshly ground pepper to taste
1/2 cup feta cheese
1 small jar roasted red peppers drained
4 onion rolls, sliced

Remove stems from Portobella mushrooms and wipe them clean, then place in a shallow dish. Combine oil, vinegar, oregano, basil, garlic, salt and pepper in an air tight container and shake well. Pour mixture over mushrooms and let marinade at least 1 hour. The longer they marinade the better they taste. Grill mushrooms until they are tender inside. If you can't grill them you can bake them in the oven at 350F for about 15 minutes. Check them often. Meanwhile, toast yours rolls if you like. Place a mushroom on an onion roll and top with a slice of roasted red pepper and some crumbled feta cheese. Serve warm and enjoy.