To prepare the sauce: chop 1 1/2 onions and place in a saucepan with oil, fry until golden, add a sprig of rosemary, salt, pepper, cooked beetroot (to give a nice colour to the sauce), a ladle of stock and cook for 10 minutes. Add a knob of butter, blend and filter with a fine sieve. Keep the sauce warm.
Add three tablespoons of oil to a non-stick pan, with half of the onion finely chopped and the savoy cabbage leaves cut in julienne style, then brown. Add the rice, 50 g bacon cut into cubes and stir a little until the rice begins to dry up. Then pour in the wine and add a small amount of sugar and allow to evaporate.
Keep cooking whilst adding spoonfuls of stock. Season with salt and finally add the butter, the parmigiano-reggiano cheese, 4 large twists of ground black pepper, a small amount of grated nutmeg and whisk all together.
In the meantime cut the remaining bacon into cubes, fry in a pan until crispy, dry with kitchen roll and keep warm.
Place a small round mould on a plate and fill with risotto with savoy cabbage, bacon and black pepper in an onion.