Linguine with fresh tomatoes & buffalo mozzarella

1/2 cup olive oil1 tbsp butter1/2 cup onion chopped3 tbsp sliced garlic250 grams linguine2 cups ripe tomatoes, seeded & excess water removed125 g buffalo mozzarella1/4 cup romano cheese1/4 cup fresh basilIn a large pot of salted boiling water, cook pasta to al-dente.Saute onions in a pan with olive oil.When the onions are soft, add garlic & fry for 30-45 seconds.Add the tomatoes & cook for 3-5 mins, until the tomatoes are slighlty soft.Add the the pasta & give it a quick stir.Remove from heat, stir in mozzarella, romano cheese & fresh basil.Check seasoning & serve immediately.