1. Bring a pan of water to the boil then add the pasta shells. Cook for 2 minutes less than the cooking instructions suggest. The pasta shells should be al dente. Drain and rinse in cold water and set aside.
2. Add the oil to a baking dish placed over a medium heat. When the oil is hot add the crushed garlic and chilli flakes. Cook for 1 minute then add the spinach. Cook for 3 minutes or until the spinach has wilted.
6. Add the marinara sauce to the baking dish then arrange the pasta shells in a single layer on top of the sauce. Add salt and pepper to taste then sprinkle over the parmesan. Put on the lid or cover with tin foil if you don’t have a lid.