Cook pasta according to package instructions. Drain and reserve a cup of pasta cooking water.
In the meantime, in a food processor combine basil, pine nuts, garlic, parmesan cheese, salt & pepper. Pulse a few times to blend the ingredients. With the machine running, drizzle olive oil until a smooth paste forms. Set aside.
In a pan, heat the butter and heavy cream over medium-low flame. Stir in pesto, whisk to combine and turn off the heat. Add the cooked pasta, chopped tomatoes and additional grated cheese and mix well. Serve immediately.