Preheat the oven to 450°F.
Cook the pasta in boiling, salted water a few minutes less than the package instructions indicate so that it will still be firm when baked. Drain and set aside.
Pour the tomato sauce into medium bowl. Add the carrot purée and mix until well-combined.
In another small bowl, combine the ricotta, cauliflower purée, egg whites, 1/2 of the mozzarella, the garlic and pepper.