Clean the mushrooms by brushing off any dirt and slice off a small part of the stem.
Use a knife to remove the stems; you can also twist them off. Place the mushrooms upside down on an oven tray lined with parchment paper.
Chop the mushroom stems as finely as possible and add them to a bowl. Grate the fresh ginger and garlic clove.
Heat a frying pan over medium-high heat and add a bit of olive oil.
Sauté the garlic and ginger, then add the chopped mushroom stems. Stir in the soy sauce and pepper, cook for a few minutes.
Fill the mushroom caps with the mixture using a tablespoon. Press gently the filling in.
Bake in the oven for 15 minutes at 200°C (400°F).
Let the mushrooms cool for a few minutes, then sprinkle with chopped hazelnuts and cilantro leaves.
Notes
If you don’t have an oven, you can also heat the stuffed mushrooms in a frying pan. Add a little water, place the mushrooms in the pan, cover with a lid, and steam them on low heat for 8-10 minutes.