1.
Bring a large pot of water to the boil. Add mushrooms and cook for about 3 minutes. Drain and set aside to cool.
2.
Heat olive oil in a large frying pan over medium heat. Add the onion, shallot, garlic, parsley and chives. Cover, and let the vegetables sweat for a few minutes to release the aromas. Remove from heat, and stir in the breadcrumbs and lemon juice.
3.
Preheat the oven's grill. Scoop out the mushroom caps and fill with the breadcrumb mixture. Place on a baking tray. Top with grated cheese.
4.
Grill for 3 to 5 minutes, until cheese is melted. Serve hot.