1/4 cup (1 oz / 30g) freshly grated
sea salt and freshly ground black pepper,
3 tsp olive oil, for drizzling
thyme leaves, for garnish
Preheat oven to 400F (200C / Gas 6).
Wipe mushrooms clean using a damp paper towel. Remove them. Chop
stems finely and set aside. Warm oil in a frying pan over medium
heat. Add garlic and onion and cook until onion softens, about 2
minutes. Stir in chopped mushroom stems and cook until they soften,
Remove from heat and add parsley,
marjoram, thyme, breadcrumbs, parmesan and salt and pepper to taste.
Mix well. Divide mixture among mushroom caps, packing it well.
Place filled mushrooms, filled side
up, on a parchment-lined (baking paper-lined) baking sheet. Drizzle
with extra olive oil. Bake until golden, 15-20 minutes.