First, halve the onions and then slice them into the thinnest possible lengthwise strips. Place the sliced onions in a large bowl with half a teaspoon of brown sugar and one teaspoon of salt. Cover and let stand for at least 4 hours to allow the onions to release all their water. In the meantime, prepare two liters of vegetable broth.
In a shallow, thick-bottomed pot, add a few tablespoons of olive oil, the sliced onions, sage, and bay leaves. Cover and let them stew on low heat for the first half hour.
Add two ladles of broth, cover again, and let it cook for at least two hours, adding a ladle of broth from time to time. The result should be almost creamy. At the end, season with salt, pepper, and a pinch of cinnamon. Towards the end, also toast a few slices of bread in the oven.
Serve the onion soup as follows: Place a slice of bread at the bottom of the bowl, add a splash of extra virgin olive oil, and generously sprinkle with Pecorino. Pour the onion soup over the bread, sprinkle more Pecorino on top, and finish with another splash of olive oil.
The creaminess of the soup combined with the strong, spicy flavor of the sheep's cheese is the perfect complement to the acidity and tannins of the Chianti Classico Pruneto 2021.
