Wash the meat, dab dry and cut into small pieces. Heat the oil in a frying pan and fry the chicken breasts for about five minutes, turning them over. In the meantime, peel and finely dice the onions. Peel the garlic and press it through a garlic press. Remove the chicken from the pan. Fry the onions and garlic in the frying fat, add the rice, deglaze with 400 millilitres of stock, bring to the boil and allow to swell over a low heat for 20 minutes.
In the meantime, cut out 1/3 lengthwise from the bell pepper. Clean and wash the peppers. Bring the remaining stock to the boil. Stir the mascarpone, peas and chicken into the rice and season with salt and pepper. Fill the rice into the peppers, put them into an ovenproof dish, place the paprika lid on top, pour the remaining stock over it and cook in the preheated oven (electric cooker: 200°C/ gas: level 3) for 20 minutes. Remove the peppers from the mould, arrange on plates and serve garnished with basil