Heat the oil in a pan. Add the garlic and oregano, stir for a minute then add the tinned cherry tomatoes. Rinse the tin out with a glass of water, add this liquid to the pan too. Season with salt and pepper and gently simmer for 10 minutes. Add the spinach and cook for another 2 minutes, before folding in the mascarpone.
Meanwhile bring a pan of lightly salted water to the boil, add the pasta and cook it for 10-12 minutes, until Al Dente. (Follow the packaging instructions!) Drain the pasta and add to the pasta sauce, which should be ready at the same time.
Stir through and serve warm with some grated Parmesan and freshly ground pepper.