Peel the onions and boil them whole in plenty of salted water, with a tablespoon of vinegar, for 40 minutes.
Cut off the top cap and hollow out the inside, leaving the onion 'ball' as a container. Chop the pulp and keep it aside.
Meanwhile, cook the ground meat with a tablespoon of evo oil. Season with salt and pepper.
Transfer the meat to a bowl and add the egg, chopped onion, and thyme. Stir. Add 2 ounces of Gorgonzola cheese and continue stirring.
Transfer the onions to a baking dish and fill with the filling. Garnish with the remaining Gorgonzola, a drizzle of oil and black pepper.
Bake in a 200° oven for 20 minutes.
Serve the baked stuffed onions immediately.
