Wash the chicken breast fillets and pat dry. Cut a pocket with a sharp knife.
Skin all tomatoes. Core 2 for the filling and cut into small cubes. Mix Philadelphia with the mustard with a fork and add the diced tomatoes. Season to taste with salt and pepper, let it steep for a moment and then fill the chicken breasts with it. Seal with a toothpick or a roulade needle.
Brown the meat well on each side in a coated ovenproof pan. Since the inside of the breast does not cook as quickly as the outside, put the pan in the oven for another 10 minutes at 170 degrees.
Briefly sweat the rice in the butter. Pour in the water, add the granulated broth and cook the rice on the highest level without a lid. In the meantime, roughly dice the remaining tomatoes and remove the seeds as desired. I only core half at a time. When the rice has almost completely absorbed the water, add the tomatoes, reduce the heat, cover the saucepan and cook for another 5 minutes.