Cover with extra virgin olive oil the bottom of a heavy large pan and add in the butter and the chopped vegetables. Sauté for about 10 minutes, stirring frequently with a wooden spoon. Pay attention not to overcook the vegetables: they should get lightly golden and soft.
Soak the mushrooms in a cup of hot water until soft.
Add into the meat and sauté on a medium heat, stirring constantly with a wooden spoon to break up any meat lumps. Stir continuously to let the meat cook evenly and mix it to the chopped vegetables. Cook for about 20 minutes, until the moisture from the meat has evaporated. Scrape the bottom of the pan with the wooden spoon while stirring. Season with salt and pepper.
Pour in the red wine, bit by bit, not all at once. Grandma recommended to add it in three times, stirring with the wooden spoon and letting it evaporate before pouring the remaining wine. You'll need about 10 minutes.
Add the tomato sauce, stirring thoroughly to mix it with the meat. Let it simmer for about 5 minutes, then add in the squeezed and finely chopped mushrooms and the strained mushrooms water.
Partially cover and simmer for at least 1 hour and a half. Stir frequently to prevent the sauce from sticking.
Meanwhile, mum peeped out from behind my shoulders and, while I was stirring my ragù, she whispered: it will be ready when it will be covered by a few spots of grease. And it was true!