Spaghetti with fresh tomato sauce with mastiha and bocconcini

⅓ cup extra virgin olive oil and an additional 2 to 3 tablespoons for tossing the pasta
1 onion finely chopped
4 garlic cloves crushed
1 ¼ kilos ripe fresh tomatoes peeled seeded and chopped
½ cup dry white wine
1 heaping teaspoon mastiha crystals ground with ½ teaspoon salt
additional coarse salt to taste
freshly ground black or white pepper to taste
4 to 6 tablespoons fresh oregano leaves
½ kilo spaghetti cooked al dente in salted water and drained

Heat ⅓ cup olive oil in a wide, shallow pan and sauté the onions over medium heat until they soften. Add the garlic and continue sautéing for 1 more minute until softened. Add the tomatoes with all their juices. Let them simmer and add the wine. Let the mixture simmer again, lower the heat, and add the mastiha, salt, and pepper to taste. Simmer the sauce for about 20–25 minutes until it thickens. Add the oregano just before removing the pan from the heat.
While the sauce simmers, cook the spaghetti. Drain and toss with a little olive oil. Pour the hot sauce and the bocconcini over the pasta, mix, and serve immediately with some freshly ground pepper and a bit of fresh oregano.