Bring a large pot of salted water to the boil. Drop in the pasta shells a couple at a time to prevent sticking, and allow the water to come back to the boil. Reduce the heat to a gentle simmer and very gently stir the shells from time to time to prevent them from sticking to the bottom of the pan. Cook until just al dente.

Meanwhile, heat the oil in a large pan or pot over medium heat and sauté the onion until soft and transparent - about 5 minutes. Then add the garlic and sauté until soft - about another minute.

Add the chopped spinach and allow to cook down - about 3 - 4 minutes. You can add it a few handfuls at a time if it doesn’t all fit at once. If you notice a lot of water at the bottom of your pan, make space so that it can evaporate off. Season with ½ teaspoon of salt and pepper to taste.

Transfer the cooked spinach to a colander over a bowl to drain off any excess moisture and allow to cool. You can place it in the fridge to cool more quickly if you’re short on time.

Once the pasta is cooked to just al dente, use a slotted spoon to gently transfer the shells to a strainer (always be gentle with the shells to prevent them from breaking). Rinse them under cool water and give them a light drizzle with olive oil and a gentle stir to prevent them from sticking together.

Drain the cashews and make the vegan ricotta by combining the cashews, vegan cream cheese, water (as needed to blend the cashews), lemon juice, and ½ teaspoon of salt in a small food processor or blender and blending until thick and creamy. Taste and adjust the sourness and saltiness so that it resembles the flavors of ricotta.

Once the spinach is cooled and drained, transfer it to a bowl and add the vegan ricotta. Stir to combine well.

Pour ¾ of the marinara sauce into the bottom of a large baking dish. Stuff the cooked pasta shells with the spinach-ricotta filling and arrange in the baking dish. Pour over the remaining ¼ marinara sauce.

Bake in a 400 F / 200 C oven until heated through and the sauce is bubbly - about 10 - 15 minutes. (I don’t bother pre-heating the oven, I just put the pan in the oven and turn it on - saves energy). Serve hot.