Preparation
Roast the whole red onions in a wood-fired oven for about 30 minutes, until very soft and slightly caramelized. Remove, let cool, peel and roughly chop. Season with olive oil, salt, black pepper and a generous drizzle of balsamic vinegar reduction. Set aside.
Bring the vegetable stock to a boil with the saffron threads and, when it comes to a boil, add the polenta in a steady stream, stirring constantly. Cook over low heat until you obtain a creamy and smooth texture. Finish with butter, grated São Jorge cheese, salt and black pepper. Add chopped fresh chives and keep warm.
Meanwhile, toast the pine nuts in a dry frying pan until lightly golden. Set aside.
In a frying pan, heat a drizzle of olive oil with the crushed garlic clove and sage leaves. Add the black trumpet mushrooms and sauté until tender and aromatic. Season with salt and black pepper, finish with a knob of butter and lemon zest for freshness.