Preheat your oven to 350°F / 175°C. To start the sauce, heat the olive oil in a medium saucepan over medium heat.
Add the onion and garlic, cooking for about 3 minutes until the onion is soft and fragrant, stirring occasionally.
Stir in the undrained diced tomatoes, tomato sauce, dried herbs (if using), and salt.
Bring the mixture to a boil, then reduce the heat to a simmer.
Let it cook, uncovered, for about 15 minutes, or until it has thickened to your liking.
Remove from the heat and stir in the fresh herbs (if using).
Spread all but 3/4 cup (960 ml) of the sauce evenly in the bottom of an ungreased 2-quart rectangular baking dish.
While the sauce simmers, cook the jumbo pasta shells according to package directions.
Drain them well, rinse with cold water to stop the cooking process, and drain again.
For the creamy tofu filling, place the silken tofu in a blender or food processor.
Cover and blend until completely smooth.
Add the egg product (or egg), Parmesan cheese, and black pepper.
Cover and blend again just until everything is combined.
Carefully spoon about 3 tablespoons (45 ml / 1.5 fl oz) of the tofu filling into each cooked pasta shell.
Arrange the filled shells, filling-side up, on top of the sauce in your prepared baking dish. Spoon the reserved 3/4 cup (960 ml) of sauce over the tops of the shells.
Cover the dish with foil and bake for about 35 minutes, or until everything is heated through and bubbly.
Remove the foil and sprinkle the mozzarella cheese evenly over the top.
Bake, uncovered, for another 2 minutes, just until the cheese is perfectly melted.
Let the dish stand for 10 minutes before serving. This helps the shells set up. If desired, garnish with a sprinkle of fresh basil.
