• Bring a large pot of salted water to a boil. Add the pasta shells and cook them according to the package directions.
• Drain the pasta into a colander, then return it to the pot and toss it with a few dashes of olive oil. Set aside.

Make the Quick Tomato Sauce

• Coat the bottom of a medium saucepan with oil and place it over medium heat. Once the oil is hot, add the onion. Sweat the onion until softened, about 5 minutes.
• Add the garlic and sauté it with the onion 1 minute more, until very fragrant.
• Stir in the crushed tomatoes, sugar, oregano, salt and pepper. Bring the mixture to a simmer and lower the heat.
• Allow the sauce to simmer, uncovered, for 15 minutes, stirring occasionally.
• Stir in the basil and remove the sauce from the heat. Taste test and season with additional salt and pepper if desired.

Make the Vegan Ricotta Florentine

• Place the onion, garlic, cashews, milk and lemon juice into bowl of food processor. Blend until smooth, stopping to scrape down sides of bowl as needed.
• Add the tofu, salt and pepper. Pulse the machine until a thick and slightly chunky, ricotta-like texture is achieved, again, stopping to scrape down the sides of bowl as needed.
• If some space remains in food processor bowl, add the spinach and pulse until finely chopped and well blended. Otherwise, transfer mixture to a bowl and stir the spinach in by hand.
• Taste-test and season the mixture with additional salt and pepper to taste.

Make the Stuffed Shells Florentine

• Preheat the oven to 400º. Coat the bottom of a 9 inch by 9 inch baking dish or 10 inch round oven-safe skillet with about half of sauce.
• Stuff the shells with the ricotta mixture and arrange them in a single layer in the baking dish or skillet. Top with the remaining sauce.
• Cover and bake the shells for 20-25 minutes, until the sauce is bubbly.
• Remove the shells from the oven and allow them to sit for 5 minutes before serving.