Preheat the oven to 180°C (350°F).
Clean 250 grams of button mushrooms by wiping them with a damp cloth. Remove the stems and set aside.
In a bowl, mix 100 grams of grated cheese (preferably mozzarella or cheddar), 50 grams of finely chopped onion, 2 finely chopped garlic cloves, 1/4 teaspoon of black pepper powder, and salt to taste.
Stuff the cheese mixture into the mushroom caps, pressing gently to ensure the filling stays in place.
Grease a baking tray with 1 tablespoon of oil and place the stuffed mushrooms on it.
Bake the mushrooms in the preheated oven for 15-20 minutes, or until the cheese is melted and bubbly.
Garnish with chopped coriander leaves and serve hot with a side of tomato ketchup or your favorite dipping sauce.