Remove the stalks from the mushrooms.
Place 50g/1¾oz of butter into a sauté pan and add the mushrooms, skin-side down. Season with salt and pepper and cover with a lid. Cook gently for 15-20 minutes.
Melt another 50g/1¾oz butter in a small saucepan and brush over the cooked mushrooms.
Mix the 50g/1¾oz of the breadcrumbs with the garlic and chives and crumble in the cheese.
Mix well and divide between the top of each mushroom. Return the lid to the pan and cook for a further 5-10 minutes or until the butter starts to melt.
Meanwhile, for the aioli, put the garlic into a bowl with the egg yolks. Add the mustard, then slowly drizzle oil in and stir constantly. Mix in the parsley, paprika and lemon juice and season to taste with salt and pepper.
To finish the mushrooms, remove them from the pan, set aside and keep warm. Add the remaining breadcrumbs to the pan used for the mushrooms. Cook for five minutes until crisp and golden-brown, then sprinkle them over the mushrooms.
Serve three mushrooms per person with a little aioli.