Add the onion and cook for about 2 minutes until just beginning to soften.
Stir in the garlic and rice and cook, stirring frequently until the rice is translucent and well coated.
Pour in the white vermouth, it will bubble and steam rapidly and evaporate almost immediately. add a ladleful about 1 cup of the simmering chicken stock and cook, stirring constantly, until it is absorbed.
Continue adding the stock about 1/2 ladle at a time, allowing each addition to be absorbed before adding the next…….never allow the rice to cook dry this takes about 20-25 minutes .
Just before the rice is tender, stir in the chopped tomatoes and arugula. Shred the basil leaves and immediately stir into the risotto, continue to cook, adding more stock until the risotto is creamy and the rice is tender, but not firm to the bite
Remove from the heat. And stir in the remaining butter ,the parmesan cheese and mozzarella
Season to taste with salt and pepper
Serve immediately before the mozzarella melts completely