Melt 50 g of butter and two tablespoons of oil in a high-sided pan. Add the peeled and chopped onion, the minced beef and let it brown for five minutes. Pour in the white wine, let it evaporate and add the tomato puree. Season with salt and pepper and cook for about 30 minutes over medium heat, until the sauce has thickened.

Add the rice and cook it, adding the meat broth one ladle at a time. Turn off the heat, stir in the remaining butter and, when the rice is lukewarm, add two beaten eggs. Mix well and pour the mixture into a bowl to cool completely.

Cut the sweet Provolone Valpadana DOP into cubes. Form the supplì by taking about 100 g of rice mixture, taking care to insert a few cubes of cheese in the center and give them an oval shape.

Pass the supplì through the two remaining well-beaten eggs, and finally through the breadcrumbs.

Fry them in plenty of hot peanut oil. Drain them on absorbent paper and serve.