No Retro. Carefully scoop a bit of the middle out with a teaspoon. Put it chopped into a non stick pan with chopped onion, tomato, crushed garlic(I use a garlic crusher) chopped courgette or green pepper if non in the fridge. Sweat it up with olive oil and seasoning. Ripe Brie(plenty of) in the slightly hollowed mushrooms, top with the mixture from the pan, onto a foil covered oven proof plate and 25 mins at gas 5 in the oven. I also skin the mushrooms whilst prepping. Very filling and full on veggie if you want that sortafing.