Blanch the tomatoes in boiling water for a minute, drain, peel, deseed and chop them into small bits; slice the mozzarella into thin segments. Heat 4 tbsp of oil in a saucepan, add the tomatoes and the oregano; season with salt and pepper.Stir, cover with lid and cook over a low heat until it is a consistent creamy sauce. Add the mozzarella and the pecorino cheese and let them melt. Cook the pasta in a saucepan with plenty of boiling salted water.Drain it al dente and pour it in a pyrex dish, greased with a drop of oil, season the pasta with the sauce and put in a 200°C preheated oven for a few minutes. Serve the pasta in the pyrex dish.