Cut the fillet into cubes, dice the tomatoes very small and chop the onions. Fry the fillet cubes in hot olive oil, allow the onions to become translucent and briefly fry the rice.
Deglaze with red wine, add the tomatoes, add the stock cube and cover the rice with hot water. Always cover the rice with water, stirring constantly, until the rice is cooked through.
Finally, season with salt and pepper and remove from the stove. Butter and parmesan with it.