Chop the onions and fry them in the olive oil in a large saucepan. Then add the rice. Stir until it shines beautifully all over. Deglaze with the white wine.
Gradually add a ladle of vegetable stock, stirring constantly. Always wait in between until the liquid has been absorbed. Add liquid until the rice is cooked firm to the bite (takes about 20-25 minutes).
In the meantime, wash the peppers, remove the inside and cut into short strips. Fry in a pan with olive oil. Wash the tomatoes and remove the stalks. Cut the tomatoes into cubes and add to the peppers. Fry briefly.
Add the vegetables to the cooked rice and stir well. Stir in the butter and cheese. Add the basil and season the risotto with salt and pepper.